diff --git a/src/HOL/Code_Numeral.thy b/src/HOL/Code_Numeral.thy
--- a/src/HOL/Code_Numeral.thy
+++ b/src/HOL/Code_Numeral.thy
@@ -1,1329 +1,1313 @@
 (*  Title:      HOL/Code_Numeral.thy
     Author:     Florian Haftmann, TU Muenchen
 *)
 
 section \<open>Numeric types for code generation onto target language numerals only\<close>
 
 theory Code_Numeral
 imports Divides Lifting Bit_Operations
 begin
 
 subsection \<open>Type of target language integers\<close>
 
 typedef integer = "UNIV :: int set"
   morphisms int_of_integer integer_of_int ..
 
 setup_lifting type_definition_integer
 
 lemma integer_eq_iff:
   "k = l \<longleftrightarrow> int_of_integer k = int_of_integer l"
   by transfer rule
 
 lemma integer_eqI:
   "int_of_integer k = int_of_integer l \<Longrightarrow> k = l"
   using integer_eq_iff [of k l] by simp
 
 lemma int_of_integer_integer_of_int [simp]:
   "int_of_integer (integer_of_int k) = k"
   by transfer rule
 
 lemma integer_of_int_int_of_integer [simp]:
   "integer_of_int (int_of_integer k) = k"
   by transfer rule
 
 instantiation integer :: ring_1
 begin
 
 lift_definition zero_integer :: integer
   is "0 :: int"
   .
 
 declare zero_integer.rep_eq [simp]
 
 lift_definition one_integer :: integer
   is "1 :: int"
   .
 
 declare one_integer.rep_eq [simp]
 
 lift_definition plus_integer :: "integer \<Rightarrow> integer \<Rightarrow> integer"
   is "plus :: int \<Rightarrow> int \<Rightarrow> int"
   .
 
 declare plus_integer.rep_eq [simp]
 
 lift_definition uminus_integer :: "integer \<Rightarrow> integer"
   is "uminus :: int \<Rightarrow> int"
   .
 
 declare uminus_integer.rep_eq [simp]
 
 lift_definition minus_integer :: "integer \<Rightarrow> integer \<Rightarrow> integer"
   is "minus :: int \<Rightarrow> int \<Rightarrow> int"
   .
 
 declare minus_integer.rep_eq [simp]
 
 lift_definition times_integer :: "integer \<Rightarrow> integer \<Rightarrow> integer"
   is "times :: int \<Rightarrow> int \<Rightarrow> int"
   .
 
 declare times_integer.rep_eq [simp]
 
 instance proof
 qed (transfer, simp add: algebra_simps)+
 
 end
 
 instance integer :: Rings.dvd ..
 
 context
   includes lifting_syntax
   notes transfer_rule_numeral [transfer_rule]
 begin
 
 lemma [transfer_rule]:
   "(pcr_integer ===> pcr_integer ===> (\<longleftrightarrow>)) (dvd) (dvd)"
   by (unfold dvd_def) transfer_prover
 
 lemma [transfer_rule]:
   "((\<longleftrightarrow>) ===> pcr_integer) of_bool of_bool"
   by (unfold of_bool_def) transfer_prover
 
 lemma [transfer_rule]:
   "((=) ===> pcr_integer) int of_nat"
   by (rule transfer_rule_of_nat) transfer_prover+
 
 lemma [transfer_rule]:
   "((=) ===> pcr_integer) (\<lambda>k. k) of_int"
 proof -
   have "((=) ===> pcr_integer) of_int of_int"
     by (rule transfer_rule_of_int) transfer_prover+
   then show ?thesis by (simp add: id_def)
 qed
 
 lemma [transfer_rule]:
   "((=) ===> pcr_integer) numeral numeral"
   by transfer_prover
 
 lemma [transfer_rule]:
   "((=) ===> (=) ===> pcr_integer) Num.sub Num.sub"
   by (unfold Num.sub_def) transfer_prover
 
 lemma [transfer_rule]:
   "(pcr_integer ===> (=) ===> pcr_integer) (^) (^)"
   by (unfold power_def) transfer_prover
 
 end
 
 lemma int_of_integer_of_nat [simp]:
   "int_of_integer (of_nat n) = of_nat n"
   by transfer rule
 
 lift_definition integer_of_nat :: "nat \<Rightarrow> integer"
   is "of_nat :: nat \<Rightarrow> int"
   .
 
 lemma integer_of_nat_eq_of_nat [code]:
   "integer_of_nat = of_nat"
   by transfer rule
 
 lemma int_of_integer_integer_of_nat [simp]:
   "int_of_integer (integer_of_nat n) = of_nat n"
   by transfer rule
 
 lift_definition nat_of_integer :: "integer \<Rightarrow> nat"
   is Int.nat
   .
 
 lemma nat_of_integer_of_nat [simp]:
   "nat_of_integer (of_nat n) = n"
   by transfer simp
 
 lemma int_of_integer_of_int [simp]:
   "int_of_integer (of_int k) = k"
   by transfer simp
 
 lemma nat_of_integer_integer_of_nat [simp]:
   "nat_of_integer (integer_of_nat n) = n"
   by transfer simp
 
 lemma integer_of_int_eq_of_int [simp, code_abbrev]:
   "integer_of_int = of_int"
   by transfer (simp add: fun_eq_iff)
 
 lemma of_int_integer_of [simp]:
   "of_int (int_of_integer k) = (k :: integer)"
   by transfer rule
 
 lemma int_of_integer_numeral [simp]:
   "int_of_integer (numeral k) = numeral k"
   by transfer rule
 
 lemma int_of_integer_sub [simp]:
   "int_of_integer (Num.sub k l) = Num.sub k l"
   by transfer rule
 
 definition integer_of_num :: "num \<Rightarrow> integer"
   where [simp]: "integer_of_num = numeral"
 
 lemma integer_of_num [code]:
   "integer_of_num Num.One = 1"
   "integer_of_num (Num.Bit0 n) = (let k = integer_of_num n in k + k)"
   "integer_of_num (Num.Bit1 n) = (let k = integer_of_num n in k + k + 1)"
   by (simp_all only: integer_of_num_def numeral.simps Let_def)
 
 lemma integer_of_num_triv:
   "integer_of_num Num.One = 1"
   "integer_of_num (Num.Bit0 Num.One) = 2"
   by simp_all
 
 instantiation integer :: "{linordered_idom, equal}"
 begin
 
 lift_definition abs_integer :: "integer \<Rightarrow> integer"
   is "abs :: int \<Rightarrow> int"
   .
 
 declare abs_integer.rep_eq [simp]
 
 lift_definition sgn_integer :: "integer \<Rightarrow> integer"
   is "sgn :: int \<Rightarrow> int"
   .
 
 declare sgn_integer.rep_eq [simp]
 
 lift_definition less_eq_integer :: "integer \<Rightarrow> integer \<Rightarrow> bool"
   is "less_eq :: int \<Rightarrow> int \<Rightarrow> bool"
   .
 
 lemma integer_less_eq_iff:
   "k \<le> l \<longleftrightarrow> int_of_integer k \<le> int_of_integer l"
   by (fact less_eq_integer.rep_eq)
 
 lift_definition less_integer :: "integer \<Rightarrow> integer \<Rightarrow> bool"
   is "less :: int \<Rightarrow> int \<Rightarrow> bool"
   .
 
 lemma integer_less_iff:
   "k < l \<longleftrightarrow> int_of_integer k < int_of_integer l"
   by (fact less_integer.rep_eq)
 
 lift_definition equal_integer :: "integer \<Rightarrow> integer \<Rightarrow> bool"
   is "HOL.equal :: int \<Rightarrow> int \<Rightarrow> bool"
   .
 
 instance
   by standard (transfer, simp add: algebra_simps equal less_le_not_le [symmetric] mult_strict_right_mono linear)+
 
 end
 
 context
   includes lifting_syntax
 begin
 
 lemma [transfer_rule]:
   \<open>(pcr_integer ===> pcr_integer ===> pcr_integer) min min\<close>
   by (unfold min_def) transfer_prover
 
 lemma [transfer_rule]:
   \<open>(pcr_integer ===> pcr_integer ===> pcr_integer) max max\<close>
   by (unfold max_def) transfer_prover
 
 end
 
 lemma int_of_integer_min [simp]:
   "int_of_integer (min k l) = min (int_of_integer k) (int_of_integer l)"
   by transfer rule
 
 lemma int_of_integer_max [simp]:
   "int_of_integer (max k l) = max (int_of_integer k) (int_of_integer l)"
   by transfer rule
 
 lemma nat_of_integer_non_positive [simp]:
   "k \<le> 0 \<Longrightarrow> nat_of_integer k = 0"
   by transfer simp
 
 lemma of_nat_of_integer [simp]:
   "of_nat (nat_of_integer k) = max 0 k"
   by transfer auto
 
 instantiation integer :: unique_euclidean_ring
 begin
 
 lift_definition divide_integer :: "integer \<Rightarrow> integer \<Rightarrow> integer"
   is "divide :: int \<Rightarrow> int \<Rightarrow> int"
   .
 
 declare divide_integer.rep_eq [simp]
 
 lift_definition modulo_integer :: "integer \<Rightarrow> integer \<Rightarrow> integer"
   is "modulo :: int \<Rightarrow> int \<Rightarrow> int"
   .
 
 declare modulo_integer.rep_eq [simp]
 
 lift_definition euclidean_size_integer :: "integer \<Rightarrow> nat"
   is "euclidean_size :: int \<Rightarrow> nat"
   .
 
 declare euclidean_size_integer.rep_eq [simp]
 
 lift_definition division_segment_integer :: "integer \<Rightarrow> integer"
   is "division_segment :: int \<Rightarrow> int"
   .
 
 declare division_segment_integer.rep_eq [simp]
 
 instance
   by (standard; transfer)
     (use mult_le_mono2 [of 1] in \<open>auto simp add: sgn_mult_abs abs_mult sgn_mult abs_mod_less sgn_mod nat_mult_distrib
      division_segment_mult division_segment_mod intro: div_eqI\<close>)
 
 end
 
 lemma [code]:
   "euclidean_size = nat_of_integer \<circ> abs"
   by (simp add: fun_eq_iff nat_of_integer.rep_eq)
 
 lemma [code]:
   "division_segment (k :: integer) = (if k \<ge> 0 then 1 else - 1)"
   by transfer (simp add: division_segment_int_def)
 
 instance integer :: unique_euclidean_ring_with_nat
   by (standard; transfer) (simp_all add: of_nat_div division_segment_int_def)
 
 instantiation integer :: ring_bit_operations
 begin
 
 lift_definition bit_integer :: \<open>integer \<Rightarrow> nat \<Rightarrow> bool\<close>
   is bit .
 
 lift_definition not_integer :: \<open>integer \<Rightarrow> integer\<close>
   is not .
 
 lift_definition and_integer :: \<open>integer \<Rightarrow> integer \<Rightarrow> integer\<close>
   is \<open>and\<close> .
 
 lift_definition or_integer :: \<open>integer \<Rightarrow> integer \<Rightarrow> integer\<close>
   is or .
 
 lift_definition xor_integer ::  \<open>integer \<Rightarrow> integer \<Rightarrow> integer\<close>
   is xor .
 
 lift_definition mask_integer :: \<open>nat \<Rightarrow> integer\<close>
   is mask .
 
 lift_definition set_bit_integer :: \<open>nat \<Rightarrow> integer \<Rightarrow> integer\<close>
   is set_bit .
 
 lift_definition unset_bit_integer :: \<open>nat \<Rightarrow> integer \<Rightarrow> integer\<close>
   is unset_bit .
 
 lift_definition flip_bit_integer :: \<open>nat \<Rightarrow> integer \<Rightarrow> integer\<close>
   is flip_bit .
 
 lift_definition push_bit_integer :: \<open>nat \<Rightarrow> integer \<Rightarrow> integer\<close>
   is push_bit .
 
 lift_definition drop_bit_integer :: \<open>nat \<Rightarrow> integer \<Rightarrow> integer\<close>
   is drop_bit .
 
 lift_definition take_bit_integer :: \<open>nat \<Rightarrow> integer \<Rightarrow> integer\<close>
   is take_bit .
 
 instance by (standard; transfer)
   (fact bit_eq_rec bits_induct bit_iff_odd push_bit_eq_mult drop_bit_eq_div take_bit_eq_mod
     bits_div_0 bits_div_by_1 bits_mod_div_trivial even_succ_div_2
     exp_div_exp_eq div_exp_eq mod_exp_eq mult_exp_mod_exp_eq div_exp_mod_exp_eq
     even_mask_div_iff even_mult_exp_div_exp_iff
     bit_and_iff bit_or_iff bit_xor_iff mask_eq_exp_minus_1
     set_bit_def bit_unset_bit_iff flip_bit_def bit_not_iff_eq minus_eq_not_minus_1)+
 
 end
 
 instance integer :: unique_euclidean_semiring_with_bit_operations ..
 
 context
   includes bit_operations_syntax
 begin
 
 lemma [code]:
   \<open>bit k n \<longleftrightarrow> odd (drop_bit n k)\<close>
   \<open>NOT k = - k - 1\<close>
   \<open>mask n = 2 ^ n - (1 :: integer)\<close>
   \<open>set_bit n k = k OR push_bit n 1\<close>
   \<open>unset_bit n k = k AND NOT (push_bit n 1)\<close>
   \<open>flip_bit n k = k XOR push_bit n 1\<close>
   \<open>push_bit n k = k * 2 ^ n\<close>
   \<open>drop_bit n k = k div 2 ^ n\<close>
   \<open>take_bit n k = k mod 2 ^ n\<close> for k :: integer
   by (fact bit_iff_odd_drop_bit not_eq_complement mask_eq_exp_minus_1
     set_bit_eq_or unset_bit_eq_and_not flip_bit_eq_xor push_bit_eq_mult drop_bit_eq_div take_bit_eq_mod)+
 
 lemma [code]:
   \<open>k AND l = (if k = 0 \<or> l = 0 then 0 else if k = - 1 then l else if l = - 1 then k
     else (k mod 2) * (l mod 2) + 2 * ((k div 2) AND (l div 2)))\<close> for k l :: integer
   by transfer (fact and_int_unfold) 
 
 lemma [code]:
   \<open>k OR l = (if k = - 1 \<or> l = - 1 then - 1 else if k = 0 then l else if l = 0 then k
     else max (k mod 2) (l mod 2) + 2 * ((k div 2) OR (l div 2)))\<close> for k l :: integer
   by transfer (fact or_int_unfold)
 
 lemma [code]:
   \<open>k XOR l = (if k = - 1 then NOT l else if l = - 1 then NOT k else if k = 0 then l else if l = 0 then k
     else \<bar>k mod 2 - l mod 2\<bar> + 2 * ((k div 2) XOR (l div 2)))\<close> for k l :: integer
   by transfer (fact xor_int_unfold)
 
 end
 
-instantiation integer :: unique_euclidean_semiring_numeral
+instantiation integer :: unique_euclidean_semiring_with_nat_division
 begin
 
 definition divmod_integer :: "num \<Rightarrow> num \<Rightarrow> integer \<times> integer"
 where
   divmod_integer'_def: "divmod_integer m n = (numeral m div numeral n, numeral m mod numeral n)"
 
 definition divmod_step_integer :: "integer \<Rightarrow> integer \<times> integer \<Rightarrow> integer \<times> integer"
 where
   "divmod_step_integer l qr = (let (q, r) = qr
-    in if r \<ge> l then (2 * q + 1, r - l)
+    in if \<bar>l\<bar> \<le> \<bar>r\<bar> then (2 * q + 1, r - l)
     else (2 * q, r))"
 
-instance proof
-  show "divmod m n = (numeral m div numeral n :: integer, numeral m mod numeral n)"
-    for m n by (fact divmod_integer'_def)
-  show "divmod_step l qr = (let (q, r) = qr
-    in if r \<ge> l then (2 * q + 1, r - l)
-    else (2 * q, r))" for l and qr :: "integer \<times> integer"
-    by (fact divmod_step_integer_def)
-qed (transfer,
-  fact le_add_diff_inverse2
-  unique_euclidean_semiring_numeral_class.div_less
-  unique_euclidean_semiring_numeral_class.mod_less
-  unique_euclidean_semiring_numeral_class.div_positive
-  unique_euclidean_semiring_numeral_class.mod_less_eq_dividend
-  unique_euclidean_semiring_numeral_class.pos_mod_bound
-  unique_euclidean_semiring_numeral_class.pos_mod_sign
-  unique_euclidean_semiring_numeral_class.mod_mult2_eq
-  unique_euclidean_semiring_numeral_class.div_mult2_eq
-  unique_euclidean_semiring_numeral_class.discrete)+
+instance by standard
+  (auto simp add: divmod_integer'_def divmod_step_integer_def integer_less_eq_iff)
 
 end
 
 declare divmod_algorithm_code [where ?'a = integer,
   folded integer_of_num_def, unfolded integer_of_num_triv,
   code]
 
 lemma integer_of_nat_0: "integer_of_nat 0 = 0"
 by transfer simp
 
 lemma integer_of_nat_1: "integer_of_nat 1 = 1"
 by transfer simp
 
 lemma integer_of_nat_numeral:
   "integer_of_nat (numeral n) = numeral n"
 by transfer simp
 
 
 subsection \<open>Code theorems for target language integers\<close>
 
 text \<open>Constructors\<close>
 
 definition Pos :: "num \<Rightarrow> integer"
 where
   [simp, code_post]: "Pos = numeral"
 
 context
   includes lifting_syntax
 begin
 
 lemma [transfer_rule]:
   \<open>((=) ===> pcr_integer) numeral Pos\<close>
   by simp transfer_prover
 
 end
 
 lemma Pos_fold [code_unfold]:
   "numeral Num.One = Pos Num.One"
   "numeral (Num.Bit0 k) = Pos (Num.Bit0 k)"
   "numeral (Num.Bit1 k) = Pos (Num.Bit1 k)"
   by simp_all
 
 definition Neg :: "num \<Rightarrow> integer"
 where
   [simp, code_abbrev]: "Neg n = - Pos n"
 
 context
   includes lifting_syntax
 begin
 
 lemma [transfer_rule]:
   \<open>((=) ===> pcr_integer) (\<lambda>n. - numeral n) Neg\<close>
   by (unfold Neg_def) transfer_prover
 
 end
 
 code_datatype "0::integer" Pos Neg
 
   
 text \<open>A further pair of constructors for generated computations\<close>
 
 context
 begin  
 
 qualified definition positive :: "num \<Rightarrow> integer"
   where [simp]: "positive = numeral"
 
 qualified definition negative :: "num \<Rightarrow> integer"
   where [simp]: "negative = uminus \<circ> numeral"
 
 lemma [code_computation_unfold]:
   "numeral = positive"
   "Pos = positive"
   "Neg = negative"
   by (simp_all add: fun_eq_iff)
 
 end
 
 
 text \<open>Auxiliary operations\<close>
 
 lift_definition dup :: "integer \<Rightarrow> integer"
   is "\<lambda>k::int. k + k"
   .
 
 lemma dup_code [code]:
   "dup 0 = 0"
   "dup (Pos n) = Pos (Num.Bit0 n)"
   "dup (Neg n) = Neg (Num.Bit0 n)"
   by (transfer, simp only: numeral_Bit0 minus_add_distrib)+
 
 lift_definition sub :: "num \<Rightarrow> num \<Rightarrow> integer"
   is "\<lambda>m n. numeral m - numeral n :: int"
   .
 
 lemma sub_code [code]:
   "sub Num.One Num.One = 0"
   "sub (Num.Bit0 m) Num.One = Pos (Num.BitM m)"
   "sub (Num.Bit1 m) Num.One = Pos (Num.Bit0 m)"
   "sub Num.One (Num.Bit0 n) = Neg (Num.BitM n)"
   "sub Num.One (Num.Bit1 n) = Neg (Num.Bit0 n)"
   "sub (Num.Bit0 m) (Num.Bit0 n) = dup (sub m n)"
   "sub (Num.Bit1 m) (Num.Bit1 n) = dup (sub m n)"
   "sub (Num.Bit1 m) (Num.Bit0 n) = dup (sub m n) + 1"
   "sub (Num.Bit0 m) (Num.Bit1 n) = dup (sub m n) - 1"
   by (transfer, simp add: dbl_def dbl_inc_def dbl_dec_def)+
 
 
 text \<open>Implementations\<close>
 
 lemma one_integer_code [code, code_unfold]:
   "1 = Pos Num.One"
   by simp
 
 lemma plus_integer_code [code]:
   "k + 0 = (k::integer)"
   "0 + l = (l::integer)"
   "Pos m + Pos n = Pos (m + n)"
   "Pos m + Neg n = sub m n"
   "Neg m + Pos n = sub n m"
   "Neg m + Neg n = Neg (m + n)"
   by (transfer, simp)+
 
 lemma uminus_integer_code [code]:
   "uminus 0 = (0::integer)"
   "uminus (Pos m) = Neg m"
   "uminus (Neg m) = Pos m"
   by simp_all
 
 lemma minus_integer_code [code]:
   "k - 0 = (k::integer)"
   "0 - l = uminus (l::integer)"
   "Pos m - Pos n = sub m n"
   "Pos m - Neg n = Pos (m + n)"
   "Neg m - Pos n = Neg (m + n)"
   "Neg m - Neg n = sub n m"
   by (transfer, simp)+
 
 lemma abs_integer_code [code]:
   "\<bar>k\<bar> = (if (k::integer) < 0 then - k else k)"
   by simp
 
 lemma sgn_integer_code [code]:
   "sgn k = (if k = 0 then 0 else if (k::integer) < 0 then - 1 else 1)"
   by simp
 
 lemma times_integer_code [code]:
   "k * 0 = (0::integer)"
   "0 * l = (0::integer)"
   "Pos m * Pos n = Pos (m * n)"
   "Pos m * Neg n = Neg (m * n)"
   "Neg m * Pos n = Neg (m * n)"
   "Neg m * Neg n = Pos (m * n)"
   by simp_all
 
 definition divmod_integer :: "integer \<Rightarrow> integer \<Rightarrow> integer \<times> integer"
 where
   "divmod_integer k l = (k div l, k mod l)"
 
 lemma fst_divmod_integer [simp]:
   "fst (divmod_integer k l) = k div l"
   by (simp add: divmod_integer_def)
 
 lemma snd_divmod_integer [simp]:
   "snd (divmod_integer k l) = k mod l"
   by (simp add: divmod_integer_def)
 
 definition divmod_abs :: "integer \<Rightarrow> integer \<Rightarrow> integer \<times> integer"
 where
   "divmod_abs k l = (\<bar>k\<bar> div \<bar>l\<bar>, \<bar>k\<bar> mod \<bar>l\<bar>)"
 
 lemma fst_divmod_abs [simp]:
   "fst (divmod_abs k l) = \<bar>k\<bar> div \<bar>l\<bar>"
   by (simp add: divmod_abs_def)
 
 lemma snd_divmod_abs [simp]:
   "snd (divmod_abs k l) = \<bar>k\<bar> mod \<bar>l\<bar>"
   by (simp add: divmod_abs_def)
 
 lemma divmod_abs_code [code]:
   "divmod_abs (Pos k) (Pos l) = divmod k l"
   "divmod_abs (Neg k) (Neg l) = divmod k l"
   "divmod_abs (Neg k) (Pos l) = divmod k l"
   "divmod_abs (Pos k) (Neg l) = divmod k l"
   "divmod_abs j 0 = (0, \<bar>j\<bar>)"
   "divmod_abs 0 j = (0, 0)"
   by (simp_all add: prod_eq_iff)
 
 lemma divmod_integer_eq_cases:
   "divmod_integer k l =
     (if k = 0 then (0, 0) else if l = 0 then (0, k) else
     (apsnd \<circ> times \<circ> sgn) l (if sgn k = sgn l
       then divmod_abs k l
       else (let (r, s) = divmod_abs k l in
         if s = 0 then (- r, 0) else (- r - 1, \<bar>l\<bar> - s))))"
 proof -
   have *: "sgn k = sgn l \<longleftrightarrow> k = 0 \<and> l = 0 \<or> 0 < l \<and> 0 < k \<or> l < 0 \<and> k < 0" for k l :: int
     by (auto simp add: sgn_if)
   have **: "- k = l * q \<longleftrightarrow> k = - (l * q)" for k l q :: int
     by auto
   show ?thesis
     by (simp add: divmod_integer_def divmod_abs_def)
       (transfer, auto simp add: * ** not_less zdiv_zminus1_eq_if zmod_zminus1_eq_if div_minus_right mod_minus_right)
 qed
 
 lemma divmod_integer_code [code]: \<^marker>\<open>contributor \<open>René Thiemann\<close>\<close> \<^marker>\<open>contributor \<open>Akihisa Yamada\<close>\<close>
   "divmod_integer k l =
    (if k = 0 then (0, 0)
     else if l > 0 then
             (if k > 0 then Code_Numeral.divmod_abs k l
              else case Code_Numeral.divmod_abs k l of (r, s) \<Rightarrow>
                   if s = 0 then (- r, 0) else (- r - 1, l - s))
     else if l = 0 then (0, k)
     else apsnd uminus
             (if k < 0 then Code_Numeral.divmod_abs k l
              else case Code_Numeral.divmod_abs k l of (r, s) \<Rightarrow>
                   if s = 0 then (- r, 0) else (- r - 1, - l - s)))"
   by (cases l "0 :: integer" rule: linorder_cases)
     (auto split: prod.splits simp add: divmod_integer_eq_cases)
 
 lemma div_integer_code [code]:
   "k div l = fst (divmod_integer k l)"
   by simp
 
 lemma mod_integer_code [code]:
   "k mod l = snd (divmod_integer k l)"
   by simp
 
 definition bit_cut_integer :: "integer \<Rightarrow> integer \<times> bool"
   where "bit_cut_integer k = (k div 2, odd k)"
 
 lemma bit_cut_integer_code [code]:
   "bit_cut_integer k = (if k = 0 then (0, False)
      else let (r, s) = Code_Numeral.divmod_abs k 2
        in (if k > 0 then r else - r - s, s = 1))"
 proof -
   have "bit_cut_integer k = (let (r, s) = divmod_integer k 2 in (r, s = 1))"
     by (simp add: divmod_integer_def bit_cut_integer_def odd_iff_mod_2_eq_one)
   then show ?thesis
     by (simp add: divmod_integer_code) (auto simp add: split_def)
 qed
 
 lemma equal_integer_code [code]:
   "HOL.equal 0 (0::integer) \<longleftrightarrow> True"
   "HOL.equal 0 (Pos l) \<longleftrightarrow> False"
   "HOL.equal 0 (Neg l) \<longleftrightarrow> False"
   "HOL.equal (Pos k) 0 \<longleftrightarrow> False"
   "HOL.equal (Pos k) (Pos l) \<longleftrightarrow> HOL.equal k l"
   "HOL.equal (Pos k) (Neg l) \<longleftrightarrow> False"
   "HOL.equal (Neg k) 0 \<longleftrightarrow> False"
   "HOL.equal (Neg k) (Pos l) \<longleftrightarrow> False"
   "HOL.equal (Neg k) (Neg l) \<longleftrightarrow> HOL.equal k l"
   by (simp_all add: equal)
 
 lemma equal_integer_refl [code nbe]:
   "HOL.equal (k::integer) k \<longleftrightarrow> True"
   by (fact equal_refl)
 
 lemma less_eq_integer_code [code]:
   "0 \<le> (0::integer) \<longleftrightarrow> True"
   "0 \<le> Pos l \<longleftrightarrow> True"
   "0 \<le> Neg l \<longleftrightarrow> False"
   "Pos k \<le> 0 \<longleftrightarrow> False"
   "Pos k \<le> Pos l \<longleftrightarrow> k \<le> l"
   "Pos k \<le> Neg l \<longleftrightarrow> False"
   "Neg k \<le> 0 \<longleftrightarrow> True"
   "Neg k \<le> Pos l \<longleftrightarrow> True"
   "Neg k \<le> Neg l \<longleftrightarrow> l \<le> k"
   by simp_all
 
 lemma less_integer_code [code]:
   "0 < (0::integer) \<longleftrightarrow> False"
   "0 < Pos l \<longleftrightarrow> True"
   "0 < Neg l \<longleftrightarrow> False"
   "Pos k < 0 \<longleftrightarrow> False"
   "Pos k < Pos l \<longleftrightarrow> k < l"
   "Pos k < Neg l \<longleftrightarrow> False"
   "Neg k < 0 \<longleftrightarrow> True"
   "Neg k < Pos l \<longleftrightarrow> True"
   "Neg k < Neg l \<longleftrightarrow> l < k"
   by simp_all
 
 lift_definition num_of_integer :: "integer \<Rightarrow> num"
   is "num_of_nat \<circ> nat"
   .
 
 lemma num_of_integer_code [code]:
   "num_of_integer k = (if k \<le> 1 then Num.One
      else let
        (l, j) = divmod_integer k 2;
        l' = num_of_integer l;
        l'' = l' + l'
      in if j = 0 then l'' else l'' + Num.One)"
 proof -
   {
     assume "int_of_integer k mod 2 = 1"
     then have "nat (int_of_integer k mod 2) = nat 1" by simp
     moreover assume *: "1 < int_of_integer k"
     ultimately have **: "nat (int_of_integer k) mod 2 = 1" by (simp add: nat_mod_distrib)
     have "num_of_nat (nat (int_of_integer k)) =
       num_of_nat (2 * (nat (int_of_integer k) div 2) + nat (int_of_integer k) mod 2)"
       by simp
     then have "num_of_nat (nat (int_of_integer k)) =
       num_of_nat (nat (int_of_integer k) div 2 + nat (int_of_integer k) div 2 + nat (int_of_integer k) mod 2)"
       by (simp add: mult_2)
     with ** have "num_of_nat (nat (int_of_integer k)) =
       num_of_nat (nat (int_of_integer k) div 2 + nat (int_of_integer k) div 2 + 1)"
       by simp
   }
   note aux = this
   show ?thesis
     by (auto simp add: num_of_integer_def nat_of_integer_def Let_def case_prod_beta
       not_le integer_eq_iff less_eq_integer_def
       nat_mult_distrib nat_div_distrib num_of_nat_One num_of_nat_plus_distrib
        mult_2 [where 'a=nat] aux add_One)
 qed
 
 lemma nat_of_integer_code [code]:
   "nat_of_integer k = (if k \<le> 0 then 0
      else let
        (l, j) = divmod_integer k 2;
        l' = nat_of_integer l;
        l'' = l' + l'
      in if j = 0 then l'' else l'' + 1)"
 proof -
   obtain j where k: "k = integer_of_int j"
   proof
     show "k = integer_of_int (int_of_integer k)" by simp
   qed
   have *: "nat j mod 2 = nat_of_integer (of_int j mod 2)" if "j \<ge> 0"
     using that by transfer (simp add: nat_mod_distrib)
   from k show ?thesis
     by (auto simp add: split_def Let_def nat_of_integer_def nat_div_distrib mult_2 [symmetric]
       minus_mod_eq_mult_div [symmetric] *)
 qed
 
 lemma int_of_integer_code [code]:
   "int_of_integer k = (if k < 0 then - (int_of_integer (- k))
      else if k = 0 then 0
      else let
        (l, j) = divmod_integer k 2;
        l' = 2 * int_of_integer l
      in if j = 0 then l' else l' + 1)"
   by (auto simp add: split_def Let_def integer_eq_iff minus_mod_eq_mult_div [symmetric])
 
 lemma integer_of_int_code [code]:
   "integer_of_int k = (if k < 0 then - (integer_of_int (- k))
      else if k = 0 then 0
      else let
        l = 2 * integer_of_int (k div 2);
        j = k mod 2
      in if j = 0 then l else l + 1)"
   by (auto simp add: split_def Let_def integer_eq_iff minus_mod_eq_mult_div [symmetric])
 
 hide_const (open) Pos Neg sub dup divmod_abs
 
 
 subsection \<open>Serializer setup for target language integers\<close>
 
 code_reserved Eval int Integer abs
 
 code_printing
   type_constructor integer \<rightharpoonup>
     (SML) "IntInf.int"
     and (OCaml) "Z.t"
     and (Haskell) "Integer"
     and (Scala) "BigInt"
     and (Eval) "int"
 | class_instance integer :: equal \<rightharpoonup>
     (Haskell) -
 
 code_printing
   constant "0::integer" \<rightharpoonup>
     (SML) "!(0/ :/ IntInf.int)"
     and (OCaml) "Z.zero"
     and (Haskell) "!(0/ ::/ Integer)"
     and (Scala) "BigInt(0)"
 
 setup \<open>
   fold (fn target =>
     Numeral.add_code \<^const_name>\<open>Code_Numeral.Pos\<close> I Code_Printer.literal_numeral target
     #> Numeral.add_code \<^const_name>\<open>Code_Numeral.Neg\<close> (~) Code_Printer.literal_numeral target)
     ["SML", "OCaml", "Haskell", "Scala"]
 \<close>
 
 code_printing
   constant "plus :: integer \<Rightarrow> _ \<Rightarrow> _" \<rightharpoonup>
     (SML) "IntInf.+ ((_), (_))"
     and (OCaml) "Z.add"
     and (Haskell) infixl 6 "+"
     and (Scala) infixl 7 "+"
     and (Eval) infixl 8 "+"
 | constant "uminus :: integer \<Rightarrow> _" \<rightharpoonup>
     (SML) "IntInf.~"
     and (OCaml) "Z.neg"
     and (Haskell) "negate"
     and (Scala) "!(- _)"
     and (Eval) "~/ _"
 | constant "minus :: integer \<Rightarrow> _" \<rightharpoonup>
     (SML) "IntInf.- ((_), (_))"
     and (OCaml) "Z.sub"
     and (Haskell) infixl 6 "-"
     and (Scala) infixl 7 "-"
     and (Eval) infixl 8 "-"
 | constant Code_Numeral.dup \<rightharpoonup>
     (SML) "IntInf.*/ (2,/ (_))"
     and (OCaml) "Z.shift'_left/ _/ 1"
     and (Haskell) "!(2 * _)"
     and (Scala) "!(2 * _)"
     and (Eval) "!(2 * _)"
 | constant Code_Numeral.sub \<rightharpoonup>
     (SML) "!(raise/ Fail/ \"sub\")"
     and (OCaml) "failwith/ \"sub\""
     and (Haskell) "error/ \"sub\""
     and (Scala) "!sys.error(\"sub\")"
 | constant "times :: integer \<Rightarrow> _ \<Rightarrow> _" \<rightharpoonup>
     (SML) "IntInf.* ((_), (_))"
     and (OCaml) "Z.mul"
     and (Haskell) infixl 7 "*"
     and (Scala) infixl 8 "*"
     and (Eval) infixl 9 "*"
 | constant Code_Numeral.divmod_abs \<rightharpoonup>
     (SML) "IntInf.divMod/ (IntInf.abs _,/ IntInf.abs _)"
     and (OCaml) "!(fun k l ->/ if Z.equal Z.zero l then/ (Z.zero, l) else/ Z.div'_rem/ (Z.abs k)/ (Z.abs l))"
     and (Haskell) "divMod/ (abs _)/ (abs _)"
     and (Scala) "!((k: BigInt) => (l: BigInt) =>/ if (l == 0)/ (BigInt(0), k) else/ (k.abs '/% l.abs))"
     and (Eval) "Integer.div'_mod/ (abs _)/ (abs _)"
 | constant "HOL.equal :: integer \<Rightarrow> _ \<Rightarrow> bool" \<rightharpoonup>
     (SML) "!((_ : IntInf.int) = _)"
     and (OCaml) "Z.equal"
     and (Haskell) infix 4 "=="
     and (Scala) infixl 5 "=="
     and (Eval) infixl 6 "="
 | constant "less_eq :: integer \<Rightarrow> _ \<Rightarrow> bool" \<rightharpoonup>
     (SML) "IntInf.<= ((_), (_))"
     and (OCaml) "Z.leq"
     and (Haskell) infix 4 "<="
     and (Scala) infixl 4 "<="
     and (Eval) infixl 6 "<="
 | constant "less :: integer \<Rightarrow> _ \<Rightarrow> bool" \<rightharpoonup>
     (SML) "IntInf.< ((_), (_))"
     and (OCaml) "Z.lt"
     and (Haskell) infix 4 "<"
     and (Scala) infixl 4 "<"
     and (Eval) infixl 6 "<"
 | constant "abs :: integer \<Rightarrow> _" \<rightharpoonup>
     (SML) "IntInf.abs"
     and (OCaml) "Z.abs"
     and (Haskell) "Prelude.abs"
     and (Scala) "_.abs"
     and (Eval) "abs"
 
 code_identifier
   code_module Code_Numeral \<rightharpoonup> (SML) Arith and (OCaml) Arith and (Haskell) Arith
 
 
 subsection \<open>Type of target language naturals\<close>
 
 typedef natural = "UNIV :: nat set"
   morphisms nat_of_natural natural_of_nat ..
 
 setup_lifting type_definition_natural
 
 lemma natural_eq_iff [termination_simp]:
   "m = n \<longleftrightarrow> nat_of_natural m = nat_of_natural n"
   by transfer rule
 
 lemma natural_eqI:
   "nat_of_natural m = nat_of_natural n \<Longrightarrow> m = n"
   using natural_eq_iff [of m n] by simp
 
 lemma nat_of_natural_of_nat_inverse [simp]:
   "nat_of_natural (natural_of_nat n) = n"
   by transfer rule
 
 lemma natural_of_nat_of_natural_inverse [simp]:
   "natural_of_nat (nat_of_natural n) = n"
   by transfer rule
 
 instantiation natural :: "{comm_monoid_diff, semiring_1}"
 begin
 
 lift_definition zero_natural :: natural
   is "0 :: nat"
   .
 
 declare zero_natural.rep_eq [simp]
 
 lift_definition one_natural :: natural
   is "1 :: nat"
   .
 
 declare one_natural.rep_eq [simp]
 
 lift_definition plus_natural :: "natural \<Rightarrow> natural \<Rightarrow> natural"
   is "plus :: nat \<Rightarrow> nat \<Rightarrow> nat"
   .
 
 declare plus_natural.rep_eq [simp]
 
 lift_definition minus_natural :: "natural \<Rightarrow> natural \<Rightarrow> natural"
   is "minus :: nat \<Rightarrow> nat \<Rightarrow> nat"
   .
 
 declare minus_natural.rep_eq [simp]
 
 lift_definition times_natural :: "natural \<Rightarrow> natural \<Rightarrow> natural"
   is "times :: nat \<Rightarrow> nat \<Rightarrow> nat"
   .
 
 declare times_natural.rep_eq [simp]
 
 instance proof
 qed (transfer, simp add: algebra_simps)+
 
 end
 
 instance natural :: Rings.dvd ..
 
 context
   includes lifting_syntax
 begin
 
 lemma [transfer_rule]:
   \<open>(pcr_natural ===> pcr_natural ===> (\<longleftrightarrow>)) (dvd) (dvd)\<close>
   by (unfold dvd_def) transfer_prover
 
 lemma [transfer_rule]:
   \<open>((\<longleftrightarrow>) ===> pcr_natural) of_bool of_bool\<close>
   by (unfold of_bool_def) transfer_prover
 
 lemma [transfer_rule]:
   \<open>((=) ===> pcr_natural) (\<lambda>n. n) of_nat\<close>
 proof -
   have "rel_fun HOL.eq pcr_natural (of_nat :: nat \<Rightarrow> nat) (of_nat :: nat \<Rightarrow> natural)"
     by (unfold of_nat_def) transfer_prover
   then show ?thesis by (simp add: id_def)
 qed
 
 lemma [transfer_rule]:
   \<open>((=) ===> pcr_natural) numeral numeral\<close>
 proof -
   have \<open>((=) ===> pcr_natural) numeral (\<lambda>n. of_nat (numeral n))\<close>
     by transfer_prover
   then show ?thesis by simp
 qed
 
 lemma [transfer_rule]:
   \<open>(pcr_natural ===> (=) ===> pcr_natural) (^) (^)\<close>
   by (unfold power_def) transfer_prover
 
 end
 
 lemma nat_of_natural_of_nat [simp]:
   "nat_of_natural (of_nat n) = n"
   by transfer rule
 
 lemma natural_of_nat_of_nat [simp, code_abbrev]:
   "natural_of_nat = of_nat"
   by transfer rule
 
 lemma of_nat_of_natural [simp]:
   "of_nat (nat_of_natural n) = n"
   by transfer rule
 
 lemma nat_of_natural_numeral [simp]:
   "nat_of_natural (numeral k) = numeral k"
   by transfer rule
 
 instantiation natural :: "{linordered_semiring, equal}"
 begin
 
 lift_definition less_eq_natural :: "natural \<Rightarrow> natural \<Rightarrow> bool"
   is "less_eq :: nat \<Rightarrow> nat \<Rightarrow> bool"
   .
 
 declare less_eq_natural.rep_eq [termination_simp]
 
 lift_definition less_natural :: "natural \<Rightarrow> natural \<Rightarrow> bool"
   is "less :: nat \<Rightarrow> nat \<Rightarrow> bool"
   .
 
 declare less_natural.rep_eq [termination_simp]
 
 lift_definition equal_natural :: "natural \<Rightarrow> natural \<Rightarrow> bool"
   is "HOL.equal :: nat \<Rightarrow> nat \<Rightarrow> bool"
   .
 
 instance proof
 qed (transfer, simp add: algebra_simps equal less_le_not_le [symmetric] linear)+
 
 end
 
 context
   includes lifting_syntax
 begin
 
 lemma [transfer_rule]:
   \<open>(pcr_natural ===> pcr_natural ===> pcr_natural) min min\<close>
   by (unfold min_def) transfer_prover
 
 lemma [transfer_rule]:
   \<open>(pcr_natural ===> pcr_natural ===> pcr_natural) max max\<close>
   by (unfold max_def) transfer_prover
 
 end
 
 lemma nat_of_natural_min [simp]:
   "nat_of_natural (min k l) = min (nat_of_natural k) (nat_of_natural l)"
   by transfer rule
 
 lemma nat_of_natural_max [simp]:
   "nat_of_natural (max k l) = max (nat_of_natural k) (nat_of_natural l)"
   by transfer rule
 
 instantiation natural :: unique_euclidean_semiring
 begin
 
 lift_definition divide_natural :: "natural \<Rightarrow> natural \<Rightarrow> natural"
   is "divide :: nat \<Rightarrow> nat \<Rightarrow> nat"
   .
 
 declare divide_natural.rep_eq [simp]
 
 lift_definition modulo_natural :: "natural \<Rightarrow> natural \<Rightarrow> natural"
   is "modulo :: nat \<Rightarrow> nat \<Rightarrow> nat"
   .
 
 declare modulo_natural.rep_eq [simp]
 
 lift_definition euclidean_size_natural :: "natural \<Rightarrow> nat"
   is "euclidean_size :: nat \<Rightarrow> nat"
   .
 
 declare euclidean_size_natural.rep_eq [simp]
 
 lift_definition division_segment_natural :: "natural \<Rightarrow> natural"
   is "division_segment :: nat \<Rightarrow> nat"
   .
 
 declare division_segment_natural.rep_eq [simp]
 
 instance
   by (standard; transfer)
     (auto simp add: algebra_simps unit_factor_nat_def gr0_conv_Suc)
 
 end
 
 lemma [code]:
   "euclidean_size = nat_of_natural"
   by (simp add: fun_eq_iff)
 
 lemma [code]:
   "division_segment (n::natural) = 1"
   by (simp add: natural_eq_iff)
 
 instance natural :: linordered_semidom
   by (standard; transfer) simp_all
 
 instance natural :: unique_euclidean_semiring_with_nat
   by (standard; transfer) simp_all
 
 instantiation natural :: semiring_bit_operations
 begin
 
 lift_definition bit_natural :: \<open>natural \<Rightarrow> nat \<Rightarrow> bool\<close>
   is bit .
 
 lift_definition and_natural :: \<open>natural \<Rightarrow> natural \<Rightarrow> natural\<close>
   is \<open>and\<close> .
 
 lift_definition or_natural :: \<open>natural \<Rightarrow> natural \<Rightarrow> natural\<close>
   is or .
 
 lift_definition xor_natural ::  \<open>natural \<Rightarrow> natural \<Rightarrow> natural\<close>
   is xor .
 
 lift_definition mask_natural :: \<open>nat \<Rightarrow> natural\<close>
   is mask .
 
 lift_definition set_bit_natural :: \<open>nat \<Rightarrow> natural \<Rightarrow> natural\<close>
   is set_bit .
 
 lift_definition unset_bit_natural :: \<open>nat \<Rightarrow> natural \<Rightarrow> natural\<close>
   is unset_bit .
 
 lift_definition flip_bit_natural :: \<open>nat \<Rightarrow> natural \<Rightarrow> natural\<close>
   is flip_bit .
 
 lift_definition push_bit_natural :: \<open>nat \<Rightarrow> natural \<Rightarrow> natural\<close>
   is push_bit .
 
 lift_definition drop_bit_natural :: \<open>nat \<Rightarrow> natural \<Rightarrow> natural\<close>
   is drop_bit .
 
 lift_definition take_bit_natural :: \<open>nat \<Rightarrow> natural \<Rightarrow> natural\<close>
   is take_bit .
 
 instance by (standard; transfer)
   (fact bit_eq_rec bits_induct bit_iff_odd push_bit_eq_mult drop_bit_eq_div take_bit_eq_mod
     bits_div_0 bits_div_by_1 bits_mod_div_trivial even_succ_div_2
     exp_div_exp_eq div_exp_eq mod_exp_eq mult_exp_mod_exp_eq div_exp_mod_exp_eq
     even_mask_div_iff even_mult_exp_div_exp_iff bit_and_iff bit_or_iff bit_xor_iff
     mask_eq_exp_minus_1 set_bit_def bit_unset_bit_iff flip_bit_def)+
 
 end
 
 instance natural :: unique_euclidean_semiring_with_bit_operations ..
 
 context
   includes bit_operations_syntax
 begin
 
 lemma [code]:
   \<open>bit m n \<longleftrightarrow> odd (drop_bit n m)\<close>
   \<open>mask n = 2 ^ n - (1 :: integer)\<close>
   \<open>set_bit n m = m OR push_bit n 1\<close>
   \<open>flip_bit n m = m XOR push_bit n 1\<close>
   \<open>push_bit n m = m * 2 ^ n\<close>
   \<open>drop_bit n m = m div 2 ^ n\<close>
   \<open>take_bit n m = m mod 2 ^ n\<close> for m :: natural
   by (fact bit_iff_odd_drop_bit mask_eq_exp_minus_1
     set_bit_eq_or flip_bit_eq_xor push_bit_eq_mult drop_bit_eq_div take_bit_eq_mod)+
 
 lemma [code]:
   \<open>m AND n = (if m = 0 \<or> n = 0 then 0
     else (m mod 2) * (n mod 2) + 2 * ((m div 2) AND (n div 2)))\<close> for m n :: natural
   by transfer (fact and_nat_unfold)
 
 lemma [code]:
   \<open>m OR n = (if m = 0 then n else if n = 0 then m
     else max (m mod 2) (n mod 2) + 2 * ((m div 2) OR (n div 2)))\<close> for m n :: natural
   by transfer (fact or_nat_unfold)
 
 lemma [code]:
   \<open>m XOR n = (if m = 0 then n else if n = 0 then m
     else (m mod 2 + n mod 2) mod 2 + 2 * ((m div 2) XOR (n div 2)))\<close> for m n :: natural
   by transfer (fact xor_nat_unfold)
 
 lemma [code]:
   \<open>unset_bit 0 m = 2 * (m div 2)\<close>
   \<open>unset_bit (Suc n) m = m mod 2 + 2 * unset_bit n (m div 2)\<close> for m :: natural
   by (transfer; simp add: unset_bit_Suc)+
 
 end
 
 lift_definition natural_of_integer :: "integer \<Rightarrow> natural"
   is "nat :: int \<Rightarrow> nat"
   .
 
 lift_definition integer_of_natural :: "natural \<Rightarrow> integer"
   is "of_nat :: nat \<Rightarrow> int"
   .
 
 lemma natural_of_integer_of_natural [simp]:
   "natural_of_integer (integer_of_natural n) = n"
   by transfer simp
 
 lemma integer_of_natural_of_integer [simp]:
   "integer_of_natural (natural_of_integer k) = max 0 k"
   by transfer auto
 
 lemma int_of_integer_of_natural [simp]:
   "int_of_integer (integer_of_natural n) = of_nat (nat_of_natural n)"
   by transfer rule
 
 lemma integer_of_natural_of_nat [simp]:
   "integer_of_natural (of_nat n) = of_nat n"
   by transfer rule
 
 lemma [measure_function]:
   "is_measure nat_of_natural"
   by (rule is_measure_trivial)
 
 
 subsection \<open>Inductive representation of target language naturals\<close>
 
 lift_definition Suc :: "natural \<Rightarrow> natural"
   is Nat.Suc
   .
 
 declare Suc.rep_eq [simp]
 
 old_rep_datatype "0::natural" Suc
   by (transfer, fact nat.induct nat.inject nat.distinct)+
 
 lemma natural_cases [case_names nat, cases type: natural]:
   fixes m :: natural
   assumes "\<And>n. m = of_nat n \<Longrightarrow> P"
   shows P
   using assms by transfer blast
 
 instantiation natural :: size
 begin
 
 definition size_nat where [simp, code]: "size_nat = nat_of_natural"
 
 instance ..
 
 end
 
 lemma natural_decr [termination_simp]:
   "n \<noteq> 0 \<Longrightarrow> nat_of_natural n - Nat.Suc 0 < nat_of_natural n"
   by transfer simp
 
 lemma natural_zero_minus_one: "(0::natural) - 1 = 0"
   by (rule zero_diff)
 
 lemma Suc_natural_minus_one: "Suc n - 1 = n"
   by transfer simp
 
 hide_const (open) Suc
 
 
 subsection \<open>Code refinement for target language naturals\<close>
 
 lift_definition Nat :: "integer \<Rightarrow> natural"
   is nat
   .
 
 lemma [code_post]:
   "Nat 0 = 0"
   "Nat 1 = 1"
   "Nat (numeral k) = numeral k"
   by (transfer, simp)+
 
 lemma [code abstype]:
   "Nat (integer_of_natural n) = n"
   by transfer simp
 
 lemma [code]:
   "natural_of_nat n = natural_of_integer (integer_of_nat n)"
   by transfer simp
 
 lemma [code abstract]:
   "integer_of_natural (natural_of_integer k) = max 0 k"
   by simp
 
 lemma [code]:
   \<open>integer_of_natural (mask n) = mask n\<close>
   by transfer (simp add: mask_eq_exp_minus_1 of_nat_diff)
 
 lemma [code_abbrev]:
   "natural_of_integer (Code_Numeral.Pos k) = numeral k"
   by transfer simp
 
 lemma [code abstract]:
   "integer_of_natural 0 = 0"
   by transfer simp
 
 lemma [code abstract]:
   "integer_of_natural 1 = 1"
   by transfer simp
 
 lemma [code abstract]:
   "integer_of_natural (Code_Numeral.Suc n) = integer_of_natural n + 1"
   by transfer simp
 
 lemma [code]:
   "nat_of_natural = nat_of_integer \<circ> integer_of_natural"
   by transfer (simp add: fun_eq_iff)
 
 lemma [code, code_unfold]:
   "case_natural f g n = (if n = 0 then f else g (n - 1))"
   by (cases n rule: natural.exhaust) (simp_all, simp add: Suc_def)
 
 declare natural.rec [code del]
 
 lemma [code abstract]:
   "integer_of_natural (m + n) = integer_of_natural m + integer_of_natural n"
   by transfer simp
 
 lemma [code abstract]:
   "integer_of_natural (m - n) = max 0 (integer_of_natural m - integer_of_natural n)"
   by transfer simp
 
 lemma [code abstract]:
   "integer_of_natural (m * n) = integer_of_natural m * integer_of_natural n"
   by transfer simp
 
 lemma [code abstract]:
   "integer_of_natural (m div n) = integer_of_natural m div integer_of_natural n"
   by transfer (simp add: zdiv_int)
 
 lemma [code abstract]:
   "integer_of_natural (m mod n) = integer_of_natural m mod integer_of_natural n"
   by transfer (simp add: zmod_int)
 
 lemma [code]:
   "HOL.equal m n \<longleftrightarrow> HOL.equal (integer_of_natural m) (integer_of_natural n)"
   by transfer (simp add: equal)
 
 lemma [code nbe]: "HOL.equal n (n::natural) \<longleftrightarrow> True"
   by (rule equal_class.equal_refl)
 
 lemma [code]: "m \<le> n \<longleftrightarrow> integer_of_natural m \<le> integer_of_natural n"
   by transfer simp
 
 lemma [code]: "m < n \<longleftrightarrow> integer_of_natural m < integer_of_natural n"
   by transfer simp
 
 hide_const (open) Nat
 
 code_reflect Code_Numeral
   datatypes natural
   functions "Code_Numeral.Suc" "0 :: natural" "1 :: natural"
     "plus :: natural \<Rightarrow> _" "minus :: natural \<Rightarrow> _"
     "times :: natural \<Rightarrow> _" "divide :: natural \<Rightarrow> _"
     "modulo :: natural \<Rightarrow> _"
     integer_of_natural natural_of_integer
 
 lifting_update integer.lifting
 lifting_forget integer.lifting
 
 lifting_update natural.lifting
 lifting_forget natural.lifting
 
 end
diff --git a/src/HOL/Divides.thy b/src/HOL/Divides.thy
--- a/src/HOL/Divides.thy
+++ b/src/HOL/Divides.thy
@@ -1,1091 +1,1093 @@
 (*  Title:      HOL/Divides.thy
     Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
     Copyright   1999  University of Cambridge
 *)
 
 section \<open>More on quotient and remainder\<close>
 
 theory Divides
 imports Parity
 begin
 
 subsection \<open>More on division\<close>
 
 subsubsection \<open>Monotonicity in the First Argument (Dividend)\<close>
 
 lemma unique_quotient_lemma:
   assumes "b * q' + r' \<le> b * q + r" "0 \<le> r'" "r' < b" "r < b" shows "q' \<le> (q::int)"
 proof -
   have "r' + b * (q'-q) \<le> r"
     using assms by (simp add: right_diff_distrib)
   moreover have "0 < b * (1 + q - q') "
     using assms by (simp add: right_diff_distrib distrib_left)
   moreover have "b * q' < b * (1 + q)"
     using assms by (simp add: right_diff_distrib distrib_left)
   ultimately show ?thesis
     using assms by (simp add: mult_less_cancel_left)
 qed
 
 lemma unique_quotient_lemma_neg:
   "b * q' + r' \<le> b*q + r \<Longrightarrow> r \<le> 0 \<Longrightarrow> b < r \<Longrightarrow> b < r' \<Longrightarrow> q \<le> (q'::int)"
   using unique_quotient_lemma[where b = "-b" and r = "-r'" and r'="-r"] by auto
 
 lemma zdiv_mono1:
   \<open>a div b \<le> a' div b\<close>
   if \<open>a \<le> a'\<close> \<open>0 < b\<close>
   for a b b' :: int
 proof (rule unique_quotient_lemma)
   show "b * (a div b) + a mod b \<le> b * (a' div b) + a' mod b"
     using \<open>a \<le> a'\<close> by auto
 qed (use that in auto)
 
 lemma zdiv_mono1_neg:
   fixes b::int
   assumes "a \<le> a'" "b < 0" shows "a' div b \<le> a div b"
 proof (rule unique_quotient_lemma_neg)
   show "b * (a div b) + a mod b \<le> b * (a' div b) + a' mod b"
     using assms(1) by auto
 qed (use assms in auto)
 
 
 subsubsection \<open>Monotonicity in the Second Argument (Divisor)\<close>
 
 lemma q_pos_lemma:
   fixes q'::int
   assumes "0 \<le> b'*q' + r'" "r' < b'" "0 < b'"
   shows "0 \<le> q'"
 proof -
   have "0 < b'* (q' + 1)"
     using assms by (simp add: distrib_left)
   with assms show ?thesis
     by (simp add: zero_less_mult_iff)
 qed
 
 lemma zdiv_mono2_lemma:
   fixes q'::int
   assumes eq: "b*q + r = b'*q' + r'" and le: "0 \<le> b'*q' + r'" and "r' < b'" "0 \<le> r" "0 < b'" "b' \<le> b"
   shows "q \<le> q'"
 proof -
   have "0 \<le> q'"
     using q_pos_lemma le \<open>r' < b'\<close> \<open>0 < b'\<close> by blast
   moreover have "b*q = r' - r + b'*q'"
     using eq by linarith
   ultimately have "b*q < b* (q' + 1)"
     using mult_right_mono assms unfolding distrib_left by fastforce
   with assms show ?thesis
     by (simp add: mult_less_cancel_left_pos)
 qed
 
 lemma zdiv_mono2:
   fixes a::int
   assumes "0 \<le> a" "0 < b'" "b' \<le> b" shows "a div b \<le> a div b'"
 proof (rule zdiv_mono2_lemma)
   have "b \<noteq> 0"
     using assms by linarith
   show "b * (a div b) + a mod b = b' * (a div b') + a mod b'"
     by simp
 qed (use assms in auto)
 
 lemma zdiv_mono2_neg_lemma:
     fixes q'::int
     assumes "b*q + r = b'*q' + r'" "b'*q' + r' < 0" "r < b" "0 \<le> r'" "0 < b'" "b' \<le> b"
     shows "q' \<le> q"
 proof -
   have "b'*q' < 0"
     using assms by linarith
   with assms have "q' \<le> 0"
     by (simp add: mult_less_0_iff)
   have "b*q' \<le> b'*q'"
     by (simp add: \<open>q' \<le> 0\<close> assms(6) mult_right_mono_neg)
   then have "b*q' < b* (q + 1)"
     using assms by (simp add: distrib_left)
   then show ?thesis
     using assms by (simp add: mult_less_cancel_left)
 qed
 
 lemma zdiv_mono2_neg:
   fixes a::int
   assumes "a < 0" "0 < b'" "b' \<le> b" shows "a div b' \<le> a div b"
 proof (rule zdiv_mono2_neg_lemma)
   have "b \<noteq> 0"
     using assms by linarith
   show "b * (a div b) + a mod b = b' * (a div b') + a mod b'"
     by simp
 qed (use assms in auto)
 
 
 subsubsection \<open>Computing \<open>div\<close> and \<open>mod\<close> with shifting\<close>
 
 inductive eucl_rel_int :: "int \<Rightarrow> int \<Rightarrow> int \<times> int \<Rightarrow> bool"
   where eucl_rel_int_by0: "eucl_rel_int k 0 (0, k)"
   | eucl_rel_int_dividesI: "l \<noteq> 0 \<Longrightarrow> k = q * l \<Longrightarrow> eucl_rel_int k l (q, 0)"
   | eucl_rel_int_remainderI: "sgn r = sgn l \<Longrightarrow> \<bar>r\<bar> < \<bar>l\<bar>
       \<Longrightarrow> k = q * l + r \<Longrightarrow> eucl_rel_int k l (q, r)"
 
 lemma eucl_rel_int_iff:    
   "eucl_rel_int k l (q, r) \<longleftrightarrow> 
     k = l * q + r \<and>
      (if 0 < l then 0 \<le> r \<and> r < l else if l < 0 then l < r \<and> r \<le> 0 else q = 0)"
   by (cases "r = 0")
     (auto elim!: eucl_rel_int.cases intro: eucl_rel_int_by0 eucl_rel_int_dividesI eucl_rel_int_remainderI
     simp add: ac_simps sgn_1_pos sgn_1_neg)
 
 lemma unique_quotient:
   "eucl_rel_int a b (q, r) \<Longrightarrow> eucl_rel_int a b (q', r') \<Longrightarrow> q = q'"
   apply (rule order_antisym)
    apply (simp_all add: eucl_rel_int_iff linorder_neq_iff split: if_split_asm)
      apply (blast intro: order_eq_refl [THEN unique_quotient_lemma] order_eq_refl [THEN unique_quotient_lemma_neg] sym)+
   done
 
 lemma unique_remainder:
   assumes "eucl_rel_int a b (q, r)"
     and "eucl_rel_int a b (q', r')"
   shows "r = r'"
 proof -
   have "q = q'"
     using assms by (blast intro: unique_quotient)
   then show "r = r'"
     using assms by (simp add: eucl_rel_int_iff)
 qed
 
 lemma eucl_rel_int:
   "eucl_rel_int k l (k div l, k mod l)"
 proof (cases k rule: int_cases3)
   case zero
   then show ?thesis
     by (simp add: eucl_rel_int_iff divide_int_def modulo_int_def)
 next
   case (pos n)
   then show ?thesis
     using div_mult_mod_eq [of n]
     by (cases l rule: int_cases3)
       (auto simp del: of_nat_mult of_nat_add
         simp add: mod_greater_zero_iff_not_dvd of_nat_mult [symmetric] of_nat_add [symmetric] algebra_simps
         eucl_rel_int_iff divide_int_def modulo_int_def)
 next
   case (neg n)
   then show ?thesis
     using div_mult_mod_eq [of n]
     by (cases l rule: int_cases3)
       (auto simp del: of_nat_mult of_nat_add
         simp add: mod_greater_zero_iff_not_dvd of_nat_mult [symmetric] of_nat_add [symmetric] algebra_simps
         eucl_rel_int_iff divide_int_def modulo_int_def)
 qed
 
 lemma divmod_int_unique:
   assumes "eucl_rel_int k l (q, r)"
   shows div_int_unique: "k div l = q" and mod_int_unique: "k mod l = r"
   using assms eucl_rel_int [of k l]
   using unique_quotient [of k l] unique_remainder [of k l]
   by auto
 
 lemma div_pos_geq:
   fixes k l :: int
   assumes "0 < l" and "l \<le> k"
   shows "k div l = (k - l) div l + 1"
 proof -
   have "k = (k - l) + l" by simp
   then obtain j where k: "k = j + l" ..
   with assms show ?thesis by (simp add: div_add_self2)
 qed
 
 lemma mod_pos_geq:
   fixes k l :: int
   assumes "0 < l" and "l \<le> k"
   shows "k mod l = (k - l) mod l"
 proof -
   have "k = (k - l) + l" by simp
   then obtain j where k: "k = j + l" ..
   with assms show ?thesis by simp
 qed
 
 lemma pos_eucl_rel_int_mult_2:
   assumes "0 \<le> b"
   assumes "eucl_rel_int a b (q, r)"
   shows "eucl_rel_int (1 + 2*a) (2*b) (q, 1 + 2*r)"
   using assms unfolding eucl_rel_int_iff by auto
 
 lemma neg_eucl_rel_int_mult_2:
   assumes "b \<le> 0"
   assumes "eucl_rel_int (a + 1) b (q, r)"
   shows "eucl_rel_int (1 + 2*a) (2*b) (q, 2*r - 1)"
   using assms unfolding eucl_rel_int_iff by auto
 
 text\<open>computing div by shifting\<close>
 
 lemma pos_zdiv_mult_2: "(0::int) \<le> a ==> (1 + 2*b) div (2*a) = b div a"
   using pos_eucl_rel_int_mult_2 [OF _ eucl_rel_int]
   by (rule div_int_unique)
 
 lemma neg_zdiv_mult_2:
   assumes A: "a \<le> (0::int)" shows "(1 + 2*b) div (2*a) = (b+1) div a"
   using neg_eucl_rel_int_mult_2 [OF A eucl_rel_int]
   by (rule div_int_unique)
 
 lemma zdiv_numeral_Bit0 [simp]:
   "numeral (Num.Bit0 v) div numeral (Num.Bit0 w) =
     numeral v div (numeral w :: int)"
   unfolding numeral.simps unfolding mult_2 [symmetric]
   by (rule div_mult_mult1, simp)
 
 lemma zdiv_numeral_Bit1 [simp]:
   "numeral (Num.Bit1 v) div numeral (Num.Bit0 w) =
     (numeral v div (numeral w :: int))"
   unfolding numeral.simps
   unfolding mult_2 [symmetric] add.commute [of _ 1]
   by (rule pos_zdiv_mult_2, simp)
 
 lemma pos_zmod_mult_2:
   fixes a b :: int
   assumes "0 \<le> a"
   shows "(1 + 2 * b) mod (2 * a) = 1 + 2 * (b mod a)"
   using pos_eucl_rel_int_mult_2 [OF assms eucl_rel_int]
   by (rule mod_int_unique)
 
 lemma neg_zmod_mult_2:
   fixes a b :: int
   assumes "a \<le> 0"
   shows "(1 + 2 * b) mod (2 * a) = 2 * ((b + 1) mod a) - 1"
   using neg_eucl_rel_int_mult_2 [OF assms eucl_rel_int]
   by (rule mod_int_unique)
 
 lemma zmod_numeral_Bit0 [simp]:
   "numeral (Num.Bit0 v) mod numeral (Num.Bit0 w) =
     (2::int) * (numeral v mod numeral w)"
   unfolding numeral_Bit0 [of v] numeral_Bit0 [of w]
   unfolding mult_2 [symmetric] by (rule mod_mult_mult1)
 
 lemma zmod_numeral_Bit1 [simp]:
   "numeral (Num.Bit1 v) mod numeral (Num.Bit0 w) =
     2 * (numeral v mod numeral w) + (1::int)"
   unfolding numeral_Bit1 [of v] numeral_Bit0 [of w]
   unfolding mult_2 [symmetric] add.commute [of _ 1]
   by (rule pos_zmod_mult_2, simp)
 
   
 subsubsection \<open>Quotients of Signs\<close>
 
 lemma div_eq_minus1: "0 < b \<Longrightarrow> - 1 div b = - 1" for b :: int
   by (simp add: divide_int_def)
 
 lemma zmod_minus1: "0 < b \<Longrightarrow> - 1 mod b = b - 1" for b :: int
   by (auto simp add: modulo_int_def)
 
 lemma minus_mod_int_eq:
   \<open>- k mod l = l - 1 - (k - 1) mod l\<close> if \<open>l \<ge> 0\<close> for k l :: int
 proof (cases \<open>l = 0\<close>)
   case True
   then show ?thesis
     by simp
 next
   case False
   with that have \<open>l > 0\<close>
     by simp
   then show ?thesis
   proof (cases \<open>l dvd k\<close>)
     case True
     then obtain j where \<open>k = l * j\<close> ..
     moreover have \<open>(l * j mod l - 1) mod l = l - 1\<close>
       using \<open>l > 0\<close> by (simp add: zmod_minus1)
     then have \<open>(l * j - 1) mod l = l - 1\<close>
       by (simp only: mod_simps)
     ultimately show ?thesis
       by simp
   next
     case False
     moreover have 1: \<open>0 < k mod l\<close>
       using \<open>0 < l\<close> False le_less by fastforce
     moreover have 2: \<open>k mod l < 1 + l\<close>
       using \<open>0 < l\<close> pos_mod_bound[of l k] by linarith
     from 1 2 \<open>l > 0\<close> have \<open>(k mod l - 1) mod l = k mod l - 1\<close>
       by (simp add: zmod_trivial_iff)
     ultimately show ?thesis
       by (simp only: zmod_zminus1_eq_if)
          (simp add: mod_eq_0_iff_dvd algebra_simps mod_simps)
   qed
 qed
 
 lemma div_neg_pos_less0:
   fixes a::int
   assumes "a < 0" "0 < b" 
   shows "a div b < 0"
 proof -
   have "a div b \<le> - 1 div b"
     using zdiv_mono1 assms by auto
   also have "... \<le> -1"
     by (simp add: assms(2) div_eq_minus1)
   finally show ?thesis 
     by force
 qed
 
 lemma div_nonneg_neg_le0: "[| (0::int) \<le> a; b < 0 |] ==> a div b \<le> 0"
   by (drule zdiv_mono1_neg, auto)
 
 lemma div_nonpos_pos_le0: "[| (a::int) \<le> 0; b > 0 |] ==> a div b \<le> 0"
   by (drule zdiv_mono1, auto)
 
 text\<open>Now for some equivalences of the form \<open>a div b >=< 0 \<longleftrightarrow> \<dots>\<close>
 conditional upon the sign of \<open>a\<close> or \<open>b\<close>. There are many more.
 They should all be simp rules unless that causes too much search.\<close>
 
 lemma pos_imp_zdiv_nonneg_iff:
       fixes a::int
       assumes "0 < b" 
       shows "(0 \<le> a div b) = (0 \<le> a)"
 proof
   show "0 \<le> a div b \<Longrightarrow> 0 \<le> a"
     using assms
     by (simp add: linorder_not_less [symmetric]) (blast intro: div_neg_pos_less0)
 next
   assume "0 \<le> a"
   then have "0 div b \<le> a div b"
     using zdiv_mono1 assms by blast
   then show "0 \<le> a div b"
     by auto
 qed
 
 lemma pos_imp_zdiv_pos_iff:
   "0<k \<Longrightarrow> 0 < (i::int) div k \<longleftrightarrow> k \<le> i"
   using pos_imp_zdiv_nonneg_iff[of k i] zdiv_eq_0_iff[of i k] by arith
 
 lemma neg_imp_zdiv_nonneg_iff:
   fixes a::int
   assumes "b < 0" 
   shows "(0 \<le> a div b) = (a \<le> 0)"
   using assms by (simp add: div_minus_minus [of a, symmetric] pos_imp_zdiv_nonneg_iff del: div_minus_minus)
 
 (*But not (a div b \<le> 0 iff a\<le>0); consider a=1, b=2 when a div b = 0.*)
 lemma pos_imp_zdiv_neg_iff: "(0::int) < b ==> (a div b < 0) = (a < 0)"
   by (simp add: linorder_not_le [symmetric] pos_imp_zdiv_nonneg_iff)
 
 (*Again the law fails for \<le>: consider a = -1, b = -2 when a div b = 0*)
 lemma neg_imp_zdiv_neg_iff: "b < (0::int) ==> (a div b < 0) = (0 < a)"
   by (simp add: linorder_not_le [symmetric] neg_imp_zdiv_nonneg_iff)
 
 lemma nonneg1_imp_zdiv_pos_iff:
   fixes a::int
   assumes "0 \<le> a" 
   shows "a div b > 0 \<longleftrightarrow> a \<ge> b \<and> b>0"
 proof -
   have "0 < a div b \<Longrightarrow> b \<le> a"
     using div_pos_pos_trivial[of a b] assms by arith
   moreover have "0 < a div b \<Longrightarrow> b > 0"
     using assms div_nonneg_neg_le0[of a b]  by(cases "b=0"; force)
   moreover have "b \<le> a \<and> 0 < b \<Longrightarrow> 0 < a div b"
     using int_one_le_iff_zero_less[of "a div b"] zdiv_mono1[of b a b] by simp
   ultimately show ?thesis
     by blast
 qed
 
 lemma zmod_le_nonneg_dividend: "(m::int) \<ge> 0 \<Longrightarrow> m mod k \<le> m"
   by (rule split_zmod[THEN iffD2]) (fastforce dest: q_pos_lemma intro: split_mult_pos_le)
 
 lemma sgn_div_eq_sgn_mult:
   \<open>sgn (k div l) = of_bool (k div l \<noteq> 0) * sgn (k * l)\<close>
   for k l :: int
 proof (cases \<open>k div l = 0\<close>)
   case True
   then show ?thesis
     by simp
 next
   case False
   have \<open>0 \<le> \<bar>k\<bar> div \<bar>l\<bar>\<close>
     by (cases \<open>l = 0\<close>) (simp_all add: pos_imp_zdiv_nonneg_iff)
   then have \<open>\<bar>k\<bar> div \<bar>l\<bar> \<noteq> 0 \<longleftrightarrow> 0 < \<bar>k\<bar> div \<bar>l\<bar>\<close>
     by (simp add: less_le)
   also have \<open>\<dots> \<longleftrightarrow> \<bar>k\<bar> \<ge> \<bar>l\<bar>\<close>
     using False nonneg1_imp_zdiv_pos_iff by auto
   finally have *: \<open>\<bar>k\<bar> div \<bar>l\<bar> \<noteq> 0 \<longleftrightarrow> \<bar>l\<bar> \<le> \<bar>k\<bar>\<close> .
   show ?thesis
     using \<open>0 \<le> \<bar>k\<bar> div \<bar>l\<bar>\<close> False
   by (auto simp add: div_eq_div_abs [of k l] div_eq_sgn_abs [of k l]
     sgn_mult sgn_1_pos sgn_1_neg sgn_eq_0_iff nonneg1_imp_zdiv_pos_iff * dest: sgn_not_eq_imp)
 qed
 
 
 subsubsection \<open>Further properties\<close>
 
 lemma div_int_pos_iff:
   "k div l \<ge> 0 \<longleftrightarrow> k = 0 \<or> l = 0 \<or> k \<ge> 0 \<and> l \<ge> 0
     \<or> k < 0 \<and> l < 0"
   for k l :: int
 proof (cases "k = 0 \<or> l = 0")
   case False
   then have *: "k \<noteq> 0" "l \<noteq> 0"
     by auto
   then have "0 \<le> k div l \<Longrightarrow> \<not> k < 0 \<Longrightarrow> 0 \<le> l"
     by (meson neg_imp_zdiv_neg_iff not_le not_less_iff_gr_or_eq)
   then show ?thesis
    using * by (auto simp add: pos_imp_zdiv_nonneg_iff neg_imp_zdiv_nonneg_iff)
 qed auto
 
 lemma mod_int_pos_iff:
   "k mod l \<ge> 0 \<longleftrightarrow> l dvd k \<or> l = 0 \<and> k \<ge> 0 \<or> l > 0"
   for k l :: int
 proof (cases "l > 0")
   case False
   then show ?thesis 
     by (simp add: dvd_eq_mod_eq_0) (use neg_mod_sign [of l k] in \<open>auto simp add: le_less not_less\<close>)
 qed auto
 
 text \<open>Simplify expressions in which div and mod combine numerical constants\<close>
 
 lemma int_div_pos_eq: "\<lbrakk>(a::int) = b * q + r; 0 \<le> r; r < b\<rbrakk> \<Longrightarrow> a div b = q"
   by (rule div_int_unique [of a b q r]) (simp add: eucl_rel_int_iff)
 
 lemma int_div_neg_eq: "\<lbrakk>(a::int) = b * q + r; r \<le> 0; b < r\<rbrakk> \<Longrightarrow> a div b = q"
   by (rule div_int_unique [of a b q r],
     simp add: eucl_rel_int_iff)
 
 lemma int_mod_pos_eq: "\<lbrakk>(a::int) = b * q + r; 0 \<le> r; r < b\<rbrakk> \<Longrightarrow> a mod b = r"
   by (rule mod_int_unique [of a b q r],
     simp add: eucl_rel_int_iff)
 
 lemma int_mod_neg_eq: "\<lbrakk>(a::int) = b * q + r; r \<le> 0; b < r\<rbrakk> \<Longrightarrow> a mod b = r"
   by (rule mod_int_unique [of a b q r],
     simp add: eucl_rel_int_iff)
 
 lemma abs_div: "(y::int) dvd x \<Longrightarrow> \<bar>x div y\<bar> = \<bar>x\<bar> div \<bar>y\<bar>"
   unfolding dvd_def by (cases "y=0") (auto simp add: abs_mult)
 
 text\<open>Suggested by Matthias Daum\<close>
 lemma int_power_div_base:
   fixes k :: int
   assumes "0 < m" "0 < k"
   shows "k ^ m div k = (k::int) ^ (m - Suc 0)"
 proof -
   have eq: "k ^ m = k ^ ((m - Suc 0) + Suc 0)"
     by (simp add: assms)
   show ?thesis
     using assms by (simp only: power_add eq) auto
 qed
 
 text\<open>Suggested by Matthias Daum\<close>
 lemma int_div_less_self:
   fixes x::int
   assumes "0 < x" "1 < k"
   shows  "x div k < x"
 proof -
   have "nat x div nat k < nat x"
     by (simp add: assms)
   with assms show ?thesis
     by (simp add: nat_div_distrib [symmetric])
 qed
 
 lemma mod_eq_dvd_iff_nat:
   "m mod q = n mod q \<longleftrightarrow> q dvd m - n" if "m \<ge> n" for m n q :: nat
 proof -
   have "int m mod int q = int n mod int q \<longleftrightarrow> int q dvd int m - int n"
     by (simp add: mod_eq_dvd_iff)
   with that have "int (m mod q) = int (n mod q) \<longleftrightarrow> int q dvd int (m - n)"
     by (simp only: of_nat_mod of_nat_diff)
   then show ?thesis
     by simp
 qed
 
 lemma mod_eq_nat1E:
   fixes m n q :: nat
   assumes "m mod q = n mod q" and "m \<ge> n"
   obtains s where "m = n + q * s"
 proof -
   from assms have "q dvd m - n"
     by (simp add: mod_eq_dvd_iff_nat)
   then obtain s where "m - n = q * s" ..
   with \<open>m \<ge> n\<close> have "m = n + q * s"
     by simp
   with that show thesis .
 qed
 
 lemma mod_eq_nat2E:
   fixes m n q :: nat
   assumes "m mod q = n mod q" and "n \<ge> m"
   obtains s where "n = m + q * s"
   using assms mod_eq_nat1E [of n q m] by (auto simp add: ac_simps)
 
 lemma nat_mod_eq_lemma:
   assumes "(x::nat) mod n = y mod n" and "y \<le> x"
   shows "\<exists>q. x = y + n * q"
   using assms by (rule mod_eq_nat1E) (rule exI)
 
 lemma nat_mod_eq_iff: "(x::nat) mod n = y mod n \<longleftrightarrow> (\<exists>q1 q2. x + n * q1 = y + n * q2)"
   (is "?lhs = ?rhs")
 proof
   assume H: "x mod n = y mod n"
   {assume xy: "x \<le> y"
     from H have th: "y mod n = x mod n" by simp
     from nat_mod_eq_lemma[OF th xy] have ?rhs
     proof
       fix q
       assume "y = x + n * q"
       then have "x + n * q = y + n * 0"
         by simp
       then show "\<exists>q1 q2. x + n * q1 = y + n * q2"
         by blast
     qed}
   moreover
   {assume xy: "y \<le> x"
     from nat_mod_eq_lemma[OF H xy] have ?rhs
     proof
       fix q
       assume "x = y + n * q"
       then have "x + n * 0 = y + n * q"
         by simp
       then show "\<exists>q1 q2. x + n * q1 = y + n * q2"
         by blast
     qed}
   ultimately  show ?rhs using linear[of x y] by blast
 next
   assume ?rhs then obtain q1 q2 where q12: "x + n * q1 = y + n * q2" by blast
   hence "(x + n * q1) mod n = (y + n * q2) mod n" by simp
   thus  ?lhs by simp
 qed
 
 
 subsection \<open>Numeral division with a pragmatic type class\<close>
 
 text \<open>
   The following type class contains everything necessary to formulate
   a division algorithm in ring structures with numerals, restricted
-  to its positive segments.  This is its primary motivation, and it
-  could surely be formulated using a more fine-grained, more algebraic
-  and less technical class hierarchy.
+  to its positive segments.
 \<close>
 
-class unique_euclidean_semiring_numeral = unique_euclidean_semiring_with_nat + linordered_semidom +
-  assumes div_less: "0 \<le> a \<Longrightarrow> a < b \<Longrightarrow> a div b = 0"
-    and mod_less: " 0 \<le> a \<Longrightarrow> a < b \<Longrightarrow> a mod b = a"
-    and div_positive: "0 < b \<Longrightarrow> b \<le> a \<Longrightarrow> a div b > 0"
-    and mod_less_eq_dividend: "0 \<le> a \<Longrightarrow> a mod b \<le> a"
-    and pos_mod_bound: "0 < b \<Longrightarrow> a mod b < b"
-    and pos_mod_sign: "0 < b \<Longrightarrow> 0 \<le> a mod b"
-    and mod_mult2_eq: "0 \<le> c \<Longrightarrow> a mod (b * c) = b * (a div b mod c) + a mod b"
-    and div_mult2_eq: "0 \<le> c \<Longrightarrow> a div (b * c) = a div b div c"
-  assumes discrete: "a < b \<longleftrightarrow> a + 1 \<le> b"
-  fixes divmod :: "num \<Rightarrow> num \<Rightarrow> 'a \<times> 'a"
-    and divmod_step :: "'a \<Rightarrow> 'a \<times> 'a \<Rightarrow> 'a \<times> 'a"
-  assumes divmod_def: "divmod m n = (numeral m div numeral n, numeral m mod numeral n)"
-    and divmod_step_def: "divmod_step l qr = (let (q, r) = qr
-    in if r \<ge> l then (2 * q + 1, r - l)
-    else (2 * q, r))"
-    \<comment> \<open>These are conceptually definitions but force generated code
-    to be monomorphic wrt. particular instances of this class which
-    yields a significant speedup.\<close>
+class unique_euclidean_semiring_with_nat_division = unique_euclidean_semiring_with_nat +
+  fixes divmod :: \<open>num \<Rightarrow> num \<Rightarrow> 'a \<times> 'a\<close>
+    and divmod_step :: \<open>'a \<Rightarrow> 'a \<times> 'a \<Rightarrow> 'a \<times> 'a\<close> \<comment> \<open>
+      These are conceptually definitions but force generated code
+      to be monomorphic wrt. particular instances of this class which
+      yields a significant speedup.\<close>
+  assumes divmod_def: \<open>divmod m n = (numeral m div numeral n, numeral m mod numeral n)\<close>
+    and divmod_step_def [simp]: \<open>divmod_step l (q, r) =
+      (if euclidean_size l \<le> euclidean_size r then (2 * q + 1, r - l)
+       else (2 * q, r))\<close> \<comment> \<open>
+         This is a formulation of one step (referring to one digit position)
+         in school-method division: compare the dividend at the current
+         digit position with the remainder from previous division steps
+         and evaluate accordingly.\<close>
 begin
 
-lemma divmod_digit_1:
-  assumes "0 \<le> a" "0 < b" and "b \<le> a mod (2 * b)"
-  shows "2 * (a div (2 * b)) + 1 = a div b" (is "?P")
-    and "a mod (2 * b) - b = a mod b" (is "?Q")
-proof -
-  from assms mod_less_eq_dividend [of a "2 * b"] have "b \<le> a"
-    by (auto intro: trans)
-  with \<open>0 < b\<close> have "0 < a div b" by (auto intro: div_positive)
-  then have [simp]: "1 \<le> a div b" by (simp add: discrete)
-  with \<open>0 < b\<close> have mod_less: "a mod b < b" by (simp add: pos_mod_bound)
-  define w where "w = a div b mod 2"
-  then have w_exhaust: "w = 0 \<or> w = 1" by auto
-  have mod_w: "a mod (2 * b) = a mod b + b * w"
-    by (simp add: w_def mod_mult2_eq ac_simps)
-  from assms w_exhaust have "w = 1"
-    using mod_less by (auto simp add: mod_w)
-  with mod_w have mod: "a mod (2 * b) = a mod b + b" by simp
-  have "2 * (a div (2 * b)) = a div b - w"
-    by (simp add: w_def div_mult2_eq minus_mod_eq_mult_div ac_simps)
-  with \<open>w = 1\<close> have div: "2 * (a div (2 * b)) = a div b - 1" by simp
-  then show ?P and ?Q
-    by (simp_all add: div mod add_implies_diff [symmetric])
-qed
-
-lemma divmod_digit_0:
-  assumes "0 < b" and "a mod (2 * b) < b"
-  shows "2 * (a div (2 * b)) = a div b" (is "?P")
-    and "a mod (2 * b) = a mod b" (is "?Q")
-proof -
-  define w where "w = a div b mod 2"
-  then have w_exhaust: "w = 0 \<or> w = 1" by auto
-  have mod_w: "a mod (2 * b) = a mod b + b * w"
-    by (simp add: w_def mod_mult2_eq ac_simps)
-  moreover have "b \<le> a mod b + b"
-  proof -
-    from \<open>0 < b\<close> pos_mod_sign have "0 \<le> a mod b" by blast
-    then have "0 + b \<le> a mod b + b" by (rule add_right_mono)
-    then show ?thesis by simp
-  qed
-  moreover note assms w_exhaust
-  ultimately have "w = 0" by auto
-  with mod_w have mod: "a mod (2 * b) = a mod b" by simp
-  have "2 * (a div (2 * b)) = a div b - w"
-    by (simp add: w_def div_mult2_eq minus_mod_eq_mult_div ac_simps)
-  with \<open>w = 0\<close> have div: "2 * (a div (2 * b)) = a div b" by simp
-  then show ?P and ?Q
-    by (simp_all add: div mod)
-qed
-
-lemma mod_double_modulus:
-  assumes "m > 0" "x \<ge> 0"
-  shows   "x mod (2 * m) = x mod m \<or> x mod (2 * m) = x mod m + m"
-proof (cases "x mod (2 * m) < m")
-  case True
-  thus ?thesis using assms using divmod_digit_0(2)[of m x] by auto
-next
-  case False
-  hence *: "x mod (2 * m) - m = x mod m"
-    using assms by (intro divmod_digit_1) auto
-  hence "x mod (2 * m) = x mod m + m"
-    by (subst * [symmetric], subst le_add_diff_inverse2) (use False in auto)
-  thus ?thesis by simp
-qed
-
 lemma fst_divmod:
-  "fst (divmod m n) = numeral m div numeral n"
+  \<open>fst (divmod m n) = numeral m div numeral n\<close>
   by (simp add: divmod_def)
 
 lemma snd_divmod:
-  "snd (divmod m n) = numeral m mod numeral n"
+  \<open>snd (divmod m n) = numeral m mod numeral n\<close>
   by (simp add: divmod_def)
 
 text \<open>
-  This is a formulation of one step (referring to one digit position)
-  in school-method division: compare the dividend at the current
-  digit position with the remainder from previous division steps
-  and evaluate accordingly.
-\<close>
-
-lemma divmod_step_eq [simp]:
-  "divmod_step l (q, r) = (if l \<le> r
-    then (2 * q + 1, r - l) else (2 * q, r))"
-  by (simp add: divmod_step_def)
-
-text \<open>
-  This is a formulation of school-method division.
+  Following a formulation of school-method division.
   If the divisor is smaller than the dividend, terminate.
   If not, shift the dividend to the right until termination
   occurs and then reiterate single division steps in the
   opposite direction.
 \<close>
 
 lemma divmod_divmod_step:
-  "divmod m n = (if m < n then (0, numeral m)
-    else divmod_step (numeral n) (divmod m (Num.Bit0 n)))"
-proof (cases "m < n")
-  case True then have "numeral m < numeral n" by simp
+  \<open>divmod m n = (if m < n then (0, numeral m)
+    else divmod_step (numeral n) (divmod m (Num.Bit0 n)))\<close>
+proof (cases \<open>m < n\<close>)
+  case True
   then show ?thesis
-    by (simp add: prod_eq_iff div_less mod_less fst_divmod snd_divmod)
+    by (simp add: prod_eq_iff fst_divmod snd_divmod flip: of_nat_numeral of_nat_div of_nat_mod)
 next
   case False
-  have "divmod m n =
-    divmod_step (numeral n) (numeral m div (2 * numeral n),
-      numeral m mod (2 * numeral n))"
-  proof (cases "numeral n \<le> numeral m mod (2 * numeral n)")
-    case True
-    with divmod_step_eq
-      have "divmod_step (numeral n) (numeral m div (2 * numeral n), numeral m mod (2 * numeral n)) =
-        (2 * (numeral m div (2 * numeral n)) + 1, numeral m mod (2 * numeral n) - numeral n)"
-        by simp
-    moreover from True divmod_digit_1 [of "numeral m" "numeral n"]
-      have "2 * (numeral m div (2 * numeral n)) + 1 = numeral m div numeral n"
-      and "numeral m mod (2 * numeral n) - numeral n = numeral m mod numeral n"
-      by simp_all
-    ultimately show ?thesis by (simp only: divmod_def)
-  next
-    case False then have *: "numeral m mod (2 * numeral n) < numeral n"
-      by (simp add: not_le)
-    with divmod_step_eq
-      have "divmod_step (numeral n) (numeral m div (2 * numeral n), numeral m mod (2 * numeral n)) =
-        (2 * (numeral m div (2 * numeral n)), numeral m mod (2 * numeral n))"
-        by auto
-    moreover from * divmod_digit_0 [of "numeral n" "numeral m"]
-      have "2 * (numeral m div (2 * numeral n)) = numeral m div numeral n"
-      and "numeral m mod (2 * numeral n) = numeral m mod numeral n"
-      by (simp_all only: zero_less_numeral)
-    ultimately show ?thesis by (simp only: divmod_def)
-  qed
-  then have "divmod m n =
-    divmod_step (numeral n) (numeral m div numeral (Num.Bit0 n),
-      numeral m mod numeral (Num.Bit0 n))"
-    by (simp only: numeral.simps distrib mult_1)
-  then have "divmod m n = divmod_step (numeral n) (divmod m (Num.Bit0 n))"
-    by (simp add: divmod_def)
-  with False show ?thesis by simp
+  define r s t where \<open>r = (numeral m :: nat)\<close> \<open>s = (numeral n :: nat)\<close> \<open>t = 2 * s\<close>
+  then have *: \<open>numeral m = of_nat r\<close> \<open>numeral n = of_nat s\<close> \<open>numeral (num.Bit0 n) = of_nat t\<close>
+    and \<open>\<not> s \<le> r mod s\<close>
+    by (simp_all add: not_le)
+  have t: \<open>2 * (r div t) = r div s - r div s mod 2\<close>
+    \<open>r mod t = s * (r div s mod 2) + r mod s\<close>
+    by (simp add: Rings.minus_mod_eq_mult_div Groups.mult.commute [of 2] Euclidean_Division.div_mult2_eq \<open>t = 2 * s\<close>)
+      (use mod_mult2_eq [of r s 2] in \<open>simp add: ac_simps \<open>t = 2 * s\<close>\<close>)
+  have rs: \<open>r div s mod 2 = 0 \<or> r div s mod 2 = Suc 0\<close>
+    by auto
+  from \<open>\<not> s \<le> r mod s\<close> have \<open>s \<le> r mod t \<Longrightarrow>
+     r div s = Suc (2 * (r div t)) \<and>
+     r mod s = r mod t - s\<close>
+    using rs
+    by (auto simp add: t)
+  moreover have \<open>r mod t < s \<Longrightarrow>
+     r div s = 2 * (r div t) \<and>
+     r mod s = r mod t\<close>
+    using rs
+    by (auto simp add: t)
+  ultimately show ?thesis
+    by (simp add: divmod_def prod_eq_iff split_def Let_def
+	    not_less mod_eq_0_iff_dvd Rings.mod_eq_0_iff_dvd False not_le *)
+    (simp add: flip: of_nat_numeral of_nat_mult add.commute [of 1] of_nat_div of_nat_mod of_nat_Suc of_nat_diff)
 qed
 
 text \<open>The division rewrite proper -- first, trivial results involving \<open>1\<close>\<close>
 
 lemma divmod_trivial [simp]:
   "divmod m Num.One = (numeral m, 0)"
   "divmod num.One (num.Bit0 n) = (0, Numeral1)"
   "divmod num.One (num.Bit1 n) = (0, Numeral1)"
   using divmod_divmod_step [of "Num.One"] by (simp_all add: divmod_def)
 
 text \<open>Division by an even number is a right-shift\<close>
 
 lemma divmod_cancel [simp]:
-  "divmod (Num.Bit0 m) (Num.Bit0 n) = (case divmod m n of (q, r) \<Rightarrow> (q, 2 * r))" (is ?P)
-  "divmod (Num.Bit1 m) (Num.Bit0 n) = (case divmod m n of (q, r) \<Rightarrow> (q, 2 * r + 1))" (is ?Q)
+  \<open>divmod (Num.Bit0 m) (Num.Bit0 n) = (case divmod m n of (q, r) \<Rightarrow> (q, 2 * r))\<close> (is ?P)
+  \<open>divmod (Num.Bit1 m) (Num.Bit0 n) = (case divmod m n of (q, r) \<Rightarrow> (q, 2 * r + 1))\<close> (is ?Q)
 proof -
-  have *: "\<And>q. numeral (Num.Bit0 q) = 2 * numeral q"
-    "\<And>q. numeral (Num.Bit1 q) = 2 * numeral q + 1"
-    by (simp_all only: numeral_mult numeral.simps distrib) simp_all
-  have "1 div 2 = 0" "1 mod 2 = 1" by (auto intro: div_less mod_less)
-  then show ?P and ?Q
-    by (simp_all add: fst_divmod snd_divmod prod_eq_iff split_def * [of m] * [of n] mod_mult_mult1
-      div_mult2_eq [of _ _ 2] mod_mult2_eq [of _ _ 2]
-      add.commute del: numeral_times_numeral)
+  define r s where \<open>r = (numeral m :: nat)\<close> \<open>s = (numeral n :: nat)\<close>
+  then have *: \<open>numeral m = of_nat r\<close> \<open>numeral n = of_nat s\<close>
+    \<open>numeral (num.Bit0 m) = of_nat (2 * r)\<close> \<open>numeral (num.Bit0 n) = of_nat (2 * s)\<close>
+    \<open>numeral (num.Bit1 m) = of_nat (Suc (2 * r))\<close>
+    by simp_all
+  show ?P and ?Q
+    by (simp_all add: divmod_def *)
+      (simp_all flip: of_nat_numeral of_nat_div of_nat_mod of_nat_mult add.commute [of 1] of_nat_Suc
+       add: Euclidean_Division.mod_mult_mult1 div_mult2_eq [of _ 2] mod_mult2_eq [of _ 2])
 qed
 
 text \<open>The really hard work\<close>
 
 lemma divmod_steps [simp]:
   "divmod (num.Bit0 m) (num.Bit1 n) =
       (if m \<le> n then (0, numeral (num.Bit0 m))
        else divmod_step (numeral (num.Bit1 n))
              (divmod (num.Bit0 m)
                (num.Bit0 (num.Bit1 n))))"
   "divmod (num.Bit1 m) (num.Bit1 n) =
       (if m < n then (0, numeral (num.Bit1 m))
        else divmod_step (numeral (num.Bit1 n))
              (divmod (num.Bit1 m)
                (num.Bit0 (num.Bit1 n))))"
   by (simp_all add: divmod_divmod_step)
 
-lemmas divmod_algorithm_code = divmod_step_eq divmod_trivial divmod_cancel divmod_steps  
+lemmas divmod_algorithm_code = divmod_trivial divmod_cancel divmod_steps
 
 text \<open>Special case: divisibility\<close>
 
 definition divides_aux :: "'a \<times> 'a \<Rightarrow> bool"
 where
   "divides_aux qr \<longleftrightarrow> snd qr = 0"
 
 lemma divides_aux_eq [simp]:
   "divides_aux (q, r) \<longleftrightarrow> r = 0"
   by (simp add: divides_aux_def)
 
 lemma dvd_numeral_simp [simp]:
   "numeral m dvd numeral n \<longleftrightarrow> divides_aux (divmod n m)"
   by (simp add: divmod_def mod_eq_0_iff_dvd)
 
 text \<open>Generic computation of quotient and remainder\<close>  
 
 lemma numeral_div_numeral [simp]: 
   "numeral k div numeral l = fst (divmod k l)"
   by (simp add: fst_divmod)
 
 lemma numeral_mod_numeral [simp]: 
   "numeral k mod numeral l = snd (divmod k l)"
   by (simp add: snd_divmod)
 
 lemma one_div_numeral [simp]:
   "1 div numeral n = fst (divmod num.One n)"
   by (simp add: fst_divmod)
 
 lemma one_mod_numeral [simp]:
   "1 mod numeral n = snd (divmod num.One n)"
   by (simp add: snd_divmod)
 
 text \<open>Computing congruences modulo \<open>2 ^ q\<close>\<close>
 
 lemma cong_exp_iff_simps:
   "numeral n mod numeral Num.One = 0
     \<longleftrightarrow> True"
   "numeral (Num.Bit0 n) mod numeral (Num.Bit0 q) = 0
     \<longleftrightarrow> numeral n mod numeral q = 0"
   "numeral (Num.Bit1 n) mod numeral (Num.Bit0 q) = 0
     \<longleftrightarrow> False"
   "numeral m mod numeral Num.One = (numeral n mod numeral Num.One)
     \<longleftrightarrow> True"
   "numeral Num.One mod numeral (Num.Bit0 q) = (numeral Num.One mod numeral (Num.Bit0 q))
     \<longleftrightarrow> True"
   "numeral Num.One mod numeral (Num.Bit0 q) = (numeral (Num.Bit0 n) mod numeral (Num.Bit0 q))
     \<longleftrightarrow> False"
   "numeral Num.One mod numeral (Num.Bit0 q) = (numeral (Num.Bit1 n) mod numeral (Num.Bit0 q))
     \<longleftrightarrow> (numeral n mod numeral q) = 0"
   "numeral (Num.Bit0 m) mod numeral (Num.Bit0 q) = (numeral Num.One mod numeral (Num.Bit0 q))
     \<longleftrightarrow> False"
   "numeral (Num.Bit0 m) mod numeral (Num.Bit0 q) = (numeral (Num.Bit0 n) mod numeral (Num.Bit0 q))
     \<longleftrightarrow> numeral m mod numeral q = (numeral n mod numeral q)"
   "numeral (Num.Bit0 m) mod numeral (Num.Bit0 q) = (numeral (Num.Bit1 n) mod numeral (Num.Bit0 q))
     \<longleftrightarrow> False"
   "numeral (Num.Bit1 m) mod numeral (Num.Bit0 q) = (numeral Num.One mod numeral (Num.Bit0 q))
     \<longleftrightarrow> (numeral m mod numeral q) = 0"
   "numeral (Num.Bit1 m) mod numeral (Num.Bit0 q) = (numeral (Num.Bit0 n) mod numeral (Num.Bit0 q))
     \<longleftrightarrow> False"
   "numeral (Num.Bit1 m) mod numeral (Num.Bit0 q) = (numeral (Num.Bit1 n) mod numeral (Num.Bit0 q))
     \<longleftrightarrow> numeral m mod numeral q = (numeral n mod numeral q)"
   by (auto simp add: case_prod_beta dest: arg_cong [of _ _ even])
 
 end
 
-hide_fact (open) div_less mod_less mod_less_eq_dividend mod_mult2_eq div_mult2_eq
-
-instantiation nat :: unique_euclidean_semiring_numeral
+instantiation nat :: unique_euclidean_semiring_with_nat_division
 begin
 
 definition divmod_nat :: "num \<Rightarrow> num \<Rightarrow> nat \<times> nat"
 where
   divmod'_nat_def: "divmod_nat m n = (numeral m div numeral n, numeral m mod numeral n)"
 
 definition divmod_step_nat :: "nat \<Rightarrow> nat \<times> nat \<Rightarrow> nat \<times> nat"
 where
   "divmod_step_nat l qr = (let (q, r) = qr
     in if r \<ge> l then (2 * q + 1, r - l)
     else (2 * q, r))"
 
-instance by standard
-  (auto simp add: divmod'_nat_def divmod_step_nat_def div_greater_zero_iff div_mult2_eq mod_mult2_eq)
+instance
+  by standard (simp_all add: divmod'_nat_def divmod_step_nat_def)
 
 end
 
 declare divmod_algorithm_code [where ?'a = nat, code]
 
 lemma Suc_0_div_numeral [simp]:
   fixes k l :: num
   shows "Suc 0 div numeral k = fst (divmod Num.One k)"
   by (simp_all add: fst_divmod)
 
 lemma Suc_0_mod_numeral [simp]:
   fixes k l :: num
   shows "Suc 0 mod numeral k = snd (divmod Num.One k)"
   by (simp_all add: snd_divmod)
 
-instantiation int :: unique_euclidean_semiring_numeral
+instantiation int :: unique_euclidean_semiring_with_nat_division
 begin
 
 definition divmod_int :: "num \<Rightarrow> num \<Rightarrow> int \<times> int"
 where
   "divmod_int m n = (numeral m div numeral n, numeral m mod numeral n)"
 
 definition divmod_step_int :: "int \<Rightarrow> int \<times> int \<Rightarrow> int \<times> int"
 where
   "divmod_step_int l qr = (let (q, r) = qr
-    in if r \<ge> l then (2 * q + 1, r - l)
+    in if \<bar>l\<bar> \<le> \<bar>r\<bar> then (2 * q + 1, r - l)
     else (2 * q, r))"
 
 instance
-  by standard (auto intro: zmod_le_nonneg_dividend simp add: divmod_int_def divmod_step_int_def
-    pos_imp_zdiv_pos_iff zmod_zmult2_eq zdiv_zmult2_eq)
+  by standard (auto simp add: divmod_int_def divmod_step_int_def)
 
 end
 
 declare divmod_algorithm_code [where ?'a = int, code]
 
 context
 begin
   
 qualified definition adjust_div :: "int \<times> int \<Rightarrow> int"
 where
   "adjust_div qr = (let (q, r) = qr in q + of_bool (r \<noteq> 0))"
 
 qualified lemma adjust_div_eq [simp, code]:
   "adjust_div (q, r) = q + of_bool (r \<noteq> 0)"
   by (simp add: adjust_div_def)
 
 qualified definition adjust_mod :: "num \<Rightarrow> int \<Rightarrow> int"
 where
   [simp]: "adjust_mod l r = (if r = 0 then 0 else numeral l - r)"
 
 lemma minus_numeral_div_numeral [simp]:
   "- numeral m div numeral n = - (adjust_div (divmod m n) :: int)"
 proof -
   have "int (fst (divmod m n)) = fst (divmod m n)"
     by (simp only: fst_divmod divide_int_def) auto
   then show ?thesis
     by (auto simp add: split_def Let_def adjust_div_def divides_aux_def divide_int_def)
 qed
 
 lemma minus_numeral_mod_numeral [simp]:
   "- numeral m mod numeral n = adjust_mod n (snd (divmod m n) :: int)"
 proof (cases "snd (divmod m n) = (0::int)")
   case True
   then show ?thesis
     by (simp add: mod_eq_0_iff_dvd divides_aux_def)
 next
   case False
   then have "int (snd (divmod m n)) = snd (divmod m n)" if "snd (divmod m n) \<noteq> (0::int)"
     by (simp only: snd_divmod modulo_int_def) auto
   then show ?thesis
     by (simp add: divides_aux_def adjust_div_def)
       (simp add: divides_aux_def modulo_int_def)
 qed
 
 lemma numeral_div_minus_numeral [simp]:
   "numeral m div - numeral n = - (adjust_div (divmod m n) :: int)"
 proof -
   have "int (fst (divmod m n)) = fst (divmod m n)"
     by (simp only: fst_divmod divide_int_def) auto
   then show ?thesis
     by (auto simp add: split_def Let_def adjust_div_def divides_aux_def divide_int_def)
 qed
   
 lemma numeral_mod_minus_numeral [simp]:
   "numeral m mod - numeral n = - adjust_mod n (snd (divmod m n) :: int)"
 proof (cases "snd (divmod m n) = (0::int)")
   case True
   then show ?thesis
     by (simp add: mod_eq_0_iff_dvd divides_aux_def)
 next
   case False
   then have "int (snd (divmod m n)) = snd (divmod m n)" if "snd (divmod m n) \<noteq> (0::int)"
     by (simp only: snd_divmod modulo_int_def) auto
   then show ?thesis
     by (simp add: divides_aux_def adjust_div_def)
       (simp add: divides_aux_def modulo_int_def)
 qed
 
 lemma minus_one_div_numeral [simp]:
   "- 1 div numeral n = - (adjust_div (divmod Num.One n) :: int)"
   using minus_numeral_div_numeral [of Num.One n] by simp  
 
 lemma minus_one_mod_numeral [simp]:
   "- 1 mod numeral n = adjust_mod n (snd (divmod Num.One n) :: int)"
   using minus_numeral_mod_numeral [of Num.One n] by simp
 
 lemma one_div_minus_numeral [simp]:
   "1 div - numeral n = - (adjust_div (divmod Num.One n) :: int)"
   using numeral_div_minus_numeral [of Num.One n] by simp
   
 lemma one_mod_minus_numeral [simp]:
   "1 mod - numeral n = - adjust_mod n (snd (divmod Num.One n) :: int)"
   using numeral_mod_minus_numeral [of Num.One n] by simp
 
 end
 
 lemma divmod_BitM_2_eq [simp]:
   \<open>divmod (Num.BitM m) (Num.Bit0 Num.One) = (numeral m - 1, (1 :: int))\<close>
   by (cases m) simp_all
 
 lemma div_positive_int:
   "k div l > 0" if "k \<ge> l" and "l > 0" for k l :: int
-  using that div_positive [of l k] by blast
+  using that by (simp add: nonneg1_imp_zdiv_pos_iff)
 
 
 subsubsection \<open>Dedicated simproc for calculation\<close>
 
+lemma euclidean_size_nat_less_eq_iff:
+  \<open>euclidean_size m \<le> euclidean_size n \<longleftrightarrow> m \<le> n\<close> for m n :: nat
+  by simp
+
+lemma euclidean_size_int_less_eq_iff:
+  \<open>euclidean_size k \<le> euclidean_size l \<longleftrightarrow> \<bar>k\<bar> \<le> \<bar>l\<bar>\<close> for k l :: int
+  by auto
+
 text \<open>
   There is space for improvement here: the calculation itself
   could be carried out outside the logic, and a generic simproc
   (simplifier setup) for generic calculation would be helpful. 
 \<close>
 
 simproc_setup numeral_divmod
-  ("0 div 0 :: 'a :: unique_euclidean_semiring_numeral" | "0 mod 0 :: 'a :: unique_euclidean_semiring_numeral" |
-   "0 div 1 :: 'a :: unique_euclidean_semiring_numeral" | "0 mod 1 :: 'a :: unique_euclidean_semiring_numeral" |
+  ("0 div 0 :: 'a :: unique_euclidean_semiring_with_nat_division" | "0 mod 0 :: 'a :: unique_euclidean_semiring_with_nat_division" |
+   "0 div 1 :: 'a :: unique_euclidean_semiring_with_nat_division" | "0 mod 1 :: 'a :: unique_euclidean_semiring_with_nat_division" |
    "0 div - 1 :: int" | "0 mod - 1 :: int" |
-   "0 div numeral b :: 'a :: unique_euclidean_semiring_numeral" | "0 mod numeral b :: 'a :: unique_euclidean_semiring_numeral" |
+   "0 div numeral b :: 'a :: unique_euclidean_semiring_with_nat_division" | "0 mod numeral b :: 'a :: unique_euclidean_semiring_with_nat_division" |
    "0 div - numeral b :: int" | "0 mod - numeral b :: int" |
-   "1 div 0 :: 'a :: unique_euclidean_semiring_numeral" | "1 mod 0 :: 'a :: unique_euclidean_semiring_numeral" |
-   "1 div 1 :: 'a :: unique_euclidean_semiring_numeral" | "1 mod 1 :: 'a :: unique_euclidean_semiring_numeral" |
+   "1 div 0 :: 'a :: unique_euclidean_semiring_with_nat_division" | "1 mod 0 :: 'a :: unique_euclidean_semiring_with_nat_division" |
+   "1 div 1 :: 'a :: unique_euclidean_semiring_with_nat_division" | "1 mod 1 :: 'a :: unique_euclidean_semiring_with_nat_division" |
    "1 div - 1 :: int" | "1 mod - 1 :: int" |
-   "1 div numeral b :: 'a :: unique_euclidean_semiring_numeral" | "1 mod numeral b :: 'a :: unique_euclidean_semiring_numeral" |
+   "1 div numeral b :: 'a :: unique_euclidean_semiring_with_nat_division" | "1 mod numeral b :: 'a :: unique_euclidean_semiring_with_nat_division" |
    "1 div - numeral b :: int" |"1 mod - numeral b :: int" |
    "- 1 div 0 :: int" | "- 1 mod 0 :: int" | "- 1 div 1 :: int" | "- 1 mod 1 :: int" |
    "- 1 div - 1 :: int" | "- 1 mod - 1 :: int" | "- 1 div numeral b :: int" | "- 1 mod numeral b :: int" |
    "- 1 div - numeral b :: int" | "- 1 mod - numeral b :: int" |
-   "numeral a div 0 :: 'a :: unique_euclidean_semiring_numeral" | "numeral a mod 0 :: 'a :: unique_euclidean_semiring_numeral" |
-   "numeral a div 1 :: 'a :: unique_euclidean_semiring_numeral" | "numeral a mod 1 :: 'a :: unique_euclidean_semiring_numeral" |
+   "numeral a div 0 :: 'a :: unique_euclidean_semiring_with_nat_division" | "numeral a mod 0 :: 'a :: unique_euclidean_semiring_with_nat_division" |
+   "numeral a div 1 :: 'a :: unique_euclidean_semiring_with_nat_division" | "numeral a mod 1 :: 'a :: unique_euclidean_semiring_with_nat_division" |
    "numeral a div - 1 :: int" | "numeral a mod - 1 :: int" |
-   "numeral a div numeral b :: 'a :: unique_euclidean_semiring_numeral" | "numeral a mod numeral b :: 'a :: unique_euclidean_semiring_numeral" |
+   "numeral a div numeral b :: 'a :: unique_euclidean_semiring_with_nat_division" | "numeral a mod numeral b :: 'a :: unique_euclidean_semiring_with_nat_division" |
    "numeral a div - numeral b :: int" | "numeral a mod - numeral b :: int" |
    "- numeral a div 0 :: int" | "- numeral a mod 0 :: int" |
    "- numeral a div 1 :: int" | "- numeral a mod 1 :: int" |
    "- numeral a div - 1 :: int" | "- numeral a mod - 1 :: int" |
    "- numeral a div numeral b :: int" | "- numeral a mod numeral b :: int" |
    "- numeral a div - numeral b :: int" | "- numeral a mod - numeral b :: int") =
 \<open> let
     val if_cong = the (Code.get_case_cong \<^theory> \<^const_name>\<open>If\<close>);
     fun successful_rewrite ctxt ct =
       let
         val thm = Simplifier.rewrite ctxt ct
       in if Thm.is_reflexive thm then NONE else SOME thm end;
   in fn phi =>
     let
       val simps = Morphism.fact phi (@{thms div_0 mod_0 div_by_0 mod_by_0 div_by_1 mod_by_1
         one_div_numeral one_mod_numeral minus_one_div_numeral minus_one_mod_numeral
         one_div_minus_numeral one_mod_minus_numeral
         numeral_div_numeral numeral_mod_numeral minus_numeral_div_numeral minus_numeral_mod_numeral
         numeral_div_minus_numeral numeral_mod_minus_numeral
         div_minus_minus mod_minus_minus Divides.adjust_div_eq of_bool_eq one_neq_zero
         numeral_neq_zero neg_equal_0_iff_equal arith_simps arith_special divmod_trivial
-        divmod_cancel divmod_steps divmod_step_eq fst_conv snd_conv numeral_One
+        divmod_cancel divmod_steps divmod_step_def fst_conv snd_conv numeral_One
         case_prod_beta rel_simps Divides.adjust_mod_def div_minus1_right mod_minus1_right
-        minus_minus numeral_times_numeral mult_zero_right mult_1_right}
+        minus_minus numeral_times_numeral mult_zero_right mult_1_right
+        euclidean_size_nat_less_eq_iff euclidean_size_int_less_eq_iff diff_nat_numeral nat_numeral}
         @ [@{lemma "0 = 0 \<longleftrightarrow> True" by simp}]);
       fun prepare_simpset ctxt = HOL_ss |> Simplifier.simpset_map ctxt
         (Simplifier.add_cong if_cong #> fold Simplifier.add_simp simps)
     in fn ctxt => successful_rewrite (Simplifier.put_simpset (prepare_simpset ctxt) ctxt) end
   end
 \<close>
 
 
 subsubsection \<open>Code generation\<close>
 
 definition divmod_nat :: "nat \<Rightarrow> nat \<Rightarrow> nat \<times> nat"
   where "divmod_nat m n = (m div n, m mod n)"
 
 lemma fst_divmod_nat [simp]:
   "fst (divmod_nat m n) = m div n"
   by (simp add: divmod_nat_def)
 
 lemma snd_divmod_nat [simp]:
   "snd (divmod_nat m n) = m mod n"
   by (simp add: divmod_nat_def)
 
 lemma divmod_nat_if [code]:
   "Divides.divmod_nat m n = (if n = 0 \<or> m < n then (0, m) else
     let (q, r) = Divides.divmod_nat (m - n) n in (Suc q, r))"
   by (simp add: prod_eq_iff case_prod_beta not_less le_div_geq le_mod_geq)
 
 lemma [code]:
   "m div n = fst (divmod_nat m n)"
   "m mod n = snd (divmod_nat m n)"
   by simp_all
 
 lemma [code]:
   fixes k :: int
   shows 
     "k div 0 = 0"
     "k mod 0 = k"
     "0 div k = 0"
     "0 mod k = 0"
     "k div Int.Pos Num.One = k"
     "k mod Int.Pos Num.One = 0"
     "k div Int.Neg Num.One = - k"
     "k mod Int.Neg Num.One = 0"
     "Int.Pos m div Int.Pos n = (fst (divmod m n) :: int)"
     "Int.Pos m mod Int.Pos n = (snd (divmod m n) :: int)"
     "Int.Neg m div Int.Pos n = - (Divides.adjust_div (divmod m n) :: int)"
     "Int.Neg m mod Int.Pos n = Divides.adjust_mod n (snd (divmod m n) :: int)"
     "Int.Pos m div Int.Neg n = - (Divides.adjust_div (divmod m n) :: int)"
     "Int.Pos m mod Int.Neg n = - Divides.adjust_mod n (snd (divmod m n) :: int)"
     "Int.Neg m div Int.Neg n = (fst (divmod m n) :: int)"
     "Int.Neg m mod Int.Neg n = - (snd (divmod m n) :: int)"
   by simp_all
 
 code_identifier
   code_module Divides \<rightharpoonup> (SML) Arith and (OCaml) Arith and (Haskell) Arith
 
 
 subsection \<open>Lemmas of doubtful value\<close>
 
+class unique_euclidean_semiring_numeral = unique_euclidean_semiring_with_nat + linordered_semidom +
+  assumes div_less: "0 \<le> a \<Longrightarrow> a < b \<Longrightarrow> a div b = 0"
+    and mod_less: " 0 \<le> a \<Longrightarrow> a < b \<Longrightarrow> a mod b = a"
+    and div_positive: "0 < b \<Longrightarrow> b \<le> a \<Longrightarrow> a div b > 0"
+    and mod_less_eq_dividend: "0 \<le> a \<Longrightarrow> a mod b \<le> a"
+    and pos_mod_bound: "0 < b \<Longrightarrow> a mod b < b"
+    and pos_mod_sign: "0 < b \<Longrightarrow> 0 \<le> a mod b"
+    and mod_mult2_eq: "0 \<le> c \<Longrightarrow> a mod (b * c) = b * (a div b mod c) + a mod b"
+    and div_mult2_eq: "0 \<le> c \<Longrightarrow> a div (b * c) = a div b div c"
+  assumes discrete: "a < b \<longleftrightarrow> a + 1 \<le> b"
+begin
+
+lemma divmod_digit_1:
+  assumes "0 \<le> a" "0 < b" and "b \<le> a mod (2 * b)"
+  shows "2 * (a div (2 * b)) + 1 = a div b" (is "?P")
+    and "a mod (2 * b) - b = a mod b" (is "?Q")
+proof -
+  from assms mod_less_eq_dividend [of a "2 * b"] have "b \<le> a"
+    by (auto intro: trans)
+  with \<open>0 < b\<close> have "0 < a div b" by (auto intro: div_positive)
+  then have [simp]: "1 \<le> a div b" by (simp add: discrete)
+  with \<open>0 < b\<close> have mod_less: "a mod b < b" by (simp add: pos_mod_bound)
+  define w where "w = a div b mod 2"
+  then have w_exhaust: "w = 0 \<or> w = 1" by auto
+  have mod_w: "a mod (2 * b) = a mod b + b * w"
+    by (simp add: w_def mod_mult2_eq ac_simps)
+  from assms w_exhaust have "w = 1"
+    using mod_less by (auto simp add: mod_w)
+  with mod_w have mod: "a mod (2 * b) = a mod b + b" by simp
+  have "2 * (a div (2 * b)) = a div b - w"
+    by (simp add: w_def div_mult2_eq minus_mod_eq_mult_div ac_simps)
+  with \<open>w = 1\<close> have div: "2 * (a div (2 * b)) = a div b - 1" by simp
+  then show ?P and ?Q
+    by (simp_all add: div mod add_implies_diff [symmetric])
+qed
+
+lemma divmod_digit_0:
+  assumes "0 < b" and "a mod (2 * b) < b"
+  shows "2 * (a div (2 * b)) = a div b" (is "?P")
+    and "a mod (2 * b) = a mod b" (is "?Q")
+proof -
+  define w where "w = a div b mod 2"
+  then have w_exhaust: "w = 0 \<or> w = 1" by auto
+  have mod_w: "a mod (2 * b) = a mod b + b * w"
+    by (simp add: w_def mod_mult2_eq ac_simps)
+  moreover have "b \<le> a mod b + b"
+  proof -
+    from \<open>0 < b\<close> pos_mod_sign have "0 \<le> a mod b" by blast
+    then have "0 + b \<le> a mod b + b" by (rule add_right_mono)
+    then show ?thesis by simp
+  qed
+  moreover note assms w_exhaust
+  ultimately have "w = 0" by auto
+  with mod_w have mod: "a mod (2 * b) = a mod b" by simp
+  have "2 * (a div (2 * b)) = a div b - w"
+    by (simp add: w_def div_mult2_eq minus_mod_eq_mult_div ac_simps)
+  with \<open>w = 0\<close> have div: "2 * (a div (2 * b)) = a div b" by simp
+  then show ?P and ?Q
+    by (simp_all add: div mod)
+qed
+
+lemma mod_double_modulus:
+  assumes "m > 0" "x \<ge> 0"
+  shows   "x mod (2 * m) = x mod m \<or> x mod (2 * m) = x mod m + m"
+proof (cases "x mod (2 * m) < m")
+  case True
+  thus ?thesis using assms using divmod_digit_0(2)[of m x] by auto
+next
+  case False
+  hence *: "x mod (2 * m) - m = x mod m"
+    using assms by (intro divmod_digit_1) auto
+  hence "x mod (2 * m) = x mod m + m"
+    by (subst * [symmetric], subst le_add_diff_inverse2) (use False in auto)
+  thus ?thesis by simp
+qed
+
+end
+
+hide_fact (open) div_less mod_less mod_less_eq_dividend mod_mult2_eq div_mult2_eq
+
+instance nat :: unique_euclidean_semiring_numeral
+  by standard
+    (auto simp add: div_greater_zero_iff div_mult2_eq mod_mult2_eq)
+
+instance int :: unique_euclidean_semiring_numeral
+  by standard (auto intro: zmod_le_nonneg_dividend simp add:
+    pos_imp_zdiv_pos_iff zmod_zmult2_eq zdiv_zmult2_eq)
+
 lemma div_geq: "m div n = Suc ((m - n) div n)" if "0 < n" and " \<not> m < n" for m n :: nat
   by (rule le_div_geq) (use that in \<open>simp_all add: not_less\<close>)
 
 lemma mod_geq: "m mod n = (m - n) mod n" if "\<not> m < n" for m n :: nat
   by (rule le_mod_geq) (use that in \<open>simp add: not_less\<close>)
 
 lemma mod_eq_0D: "\<exists>q. m = d * q" if "m mod d = 0" for m d :: nat
   using that by (auto simp add: mod_eq_0_iff_dvd)
 
 lemma pos_mod_conj: "0 < b \<Longrightarrow> 0 \<le> a mod b \<and> a mod b < b" for a b :: int
   by simp
 
 lemma neg_mod_conj: "b < 0 \<Longrightarrow> a mod b \<le> 0 \<and> b < a mod b" for a b :: int
   by simp
 
 lemma zmod_eq_0_iff: "m mod d = 0 \<longleftrightarrow> (\<exists>q. m = d * q)" for m d :: int
   by (auto simp add: mod_eq_0_iff_dvd)
 
 (* REVISIT: should this be generalized to all semiring_div types? *)
 lemma zmod_eq_0D [dest!]: "\<exists>q. m = d * q" if "m mod d = 0" for m d :: int
   using that by auto
 
 end
diff --git a/src/HOL/Library/IArray.thy b/src/HOL/Library/IArray.thy
--- a/src/HOL/Library/IArray.thy
+++ b/src/HOL/Library/IArray.thy
@@ -1,232 +1,234 @@
 (*  Title:      HOL/Library/IArray.thy
     Author:     Tobias Nipkow, TU Muenchen
     Author:     Jose Divasón <jose.divasonm at unirioja.es>
     Author:     Jesús Aransay <jesus-maria.aransay at unirioja.es>
 *)
 
 section \<open>Immutable Arrays with Code Generation\<close>
 
 theory IArray
 imports Main
 begin
 
 subsection \<open>Fundamental operations\<close>
 
 text \<open>Immutable arrays are lists wrapped up in an additional constructor.
 There are no update operations. Hence code generation can safely implement
 this type by efficient target language arrays.  Currently only SML is
 provided. Could be extended to other target languages and more operations.\<close>
 
 context
 begin
 
 datatype 'a iarray = IArray "'a list"
 
 qualified primrec list_of :: "'a iarray \<Rightarrow> 'a list" where
 "list_of (IArray xs) = xs"
 
 qualified definition of_fun :: "(nat \<Rightarrow> 'a) \<Rightarrow> nat \<Rightarrow> 'a iarray" where
 [simp]: "of_fun f n = IArray (map f [0..<n])"
 
 qualified definition sub :: "'a iarray \<Rightarrow> nat \<Rightarrow> 'a" (infixl "!!" 100) where
 [simp]: "as !! n = IArray.list_of as ! n"
 
 qualified definition length :: "'a iarray \<Rightarrow> nat" where
 [simp]: "length as = List.length (IArray.list_of as)"
 
 qualified definition all :: "('a \<Rightarrow> bool) \<Rightarrow> 'a iarray \<Rightarrow> bool" where
 [simp]: "all p as \<longleftrightarrow> (\<forall>a \<in> set (list_of as). p a)"
 
 qualified definition exists :: "('a \<Rightarrow> bool) \<Rightarrow> 'a iarray \<Rightarrow> bool" where
 [simp]: "exists p as \<longleftrightarrow> (\<exists>a \<in> set (list_of as). p a)"
 
 lemma of_fun_nth:
 "IArray.of_fun f n !! i = f i" if "i < n"
 using that by (simp add: map_nth)
 
 end
 
 
 subsection \<open>Generic code equations\<close>
 
 lemma [code]:
   "size (as :: 'a iarray) = Suc (IArray.length as)"
   by (cases as) simp
 
 lemma [code]:
   "size_iarray f as = Suc (size_list f (IArray.list_of as))"
   by (cases as) simp
 
 lemma [code]:
   "rec_iarray f as = f (IArray.list_of as)"
   by (cases as) simp
 
 lemma [code]:
   "case_iarray f as = f (IArray.list_of as)"
   by (cases as) simp
 
 lemma [code]:
   "set_iarray as = set (IArray.list_of as)"
   by (cases as) auto
 
 lemma [code]:
   "map_iarray f as = IArray (map f (IArray.list_of as))"
   by (cases as) auto
 
 lemma [code]:
   "rel_iarray r as bs = list_all2 r (IArray.list_of as) (IArray.list_of bs)"
   by (cases as, cases bs) auto
 
 lemma list_of_code [code]:
   "IArray.list_of as = map (\<lambda>n. as !! n) [0 ..< IArray.length as]"
   by (cases as) (simp add: map_nth)
 
 lemma [code]:
   "HOL.equal as bs \<longleftrightarrow> HOL.equal (IArray.list_of as) (IArray.list_of bs)"
   by (cases as, cases bs) (simp add: equal)
 
 lemma [code]:
   "IArray.all p = Not \<circ> IArray.exists (Not \<circ> p)"
   by (simp add: fun_eq_iff)
 
 context
   includes term_syntax
 begin
 
 lemma [code]:
   "Code_Evaluation.term_of (as :: 'a::typerep iarray) =
     Code_Evaluation.Const (STR ''IArray.iarray.IArray'') (TYPEREP('a list \<Rightarrow> 'a iarray)) <\<cdot>> (Code_Evaluation.term_of (IArray.list_of as))"
   by (subst term_of_anything) rule
 
 end
 
 
 subsection \<open>Auxiliary operations for code generation\<close>
 
 context
 begin
 
 qualified primrec tabulate :: "integer \<times> (integer \<Rightarrow> 'a) \<Rightarrow> 'a iarray" where
   "tabulate (n, f) = IArray (map (f \<circ> integer_of_nat) [0..<nat_of_integer n])"
 
 lemma [code]:
   "IArray.of_fun f n = IArray.tabulate (integer_of_nat n, f \<circ> nat_of_integer)"
   by simp
 
 qualified primrec sub' :: "'a iarray \<times> integer \<Rightarrow> 'a" where
   "sub' (as, n) = as !! nat_of_integer n"
 
 lemma [code]:
   "IArray.sub' (IArray as, n) = as ! nat_of_integer n"
   by simp
 
 lemma [code]:
   "as !! n = IArray.sub' (as, integer_of_nat n)"
   by simp
 
 qualified definition length' :: "'a iarray \<Rightarrow> integer" where
   [simp]: "length' as = integer_of_nat (List.length (IArray.list_of as))"
 
 lemma [code]:
   "IArray.length' (IArray as) = integer_of_nat (List.length as)"
   by simp
 
 lemma [code]:
   "IArray.length as = nat_of_integer (IArray.length' as)"
   by simp
 
 qualified definition exists_upto :: "('a \<Rightarrow> bool) \<Rightarrow> integer \<Rightarrow> 'a iarray \<Rightarrow> bool" where
   [simp]: "exists_upto p k as \<longleftrightarrow> (\<exists>l. 0 \<le> l \<and> l < k \<and> p (sub' (as, l)))"
 
 lemma exists_upto_of_nat:
   "exists_upto p (of_nat n) as \<longleftrightarrow> (\<exists>m<n. p (as !! m))"
   including integer.lifting by (simp, transfer)
     (metis nat_int nat_less_iff of_nat_0_le_iff)
 
 lemma [code]:
   "exists_upto p k as \<longleftrightarrow> (if k \<le> 0 then False else
     let l = k - 1 in p (sub' (as, l)) \<or> exists_upto p l as)"
 proof (cases "k \<ge> 1")
   case False
+  then have \<open>k \<le> 0\<close>
+    including integer.lifting by transfer simp
   then show ?thesis
-    by (auto simp add: not_le discrete)
+    by simp
 next
   case True
   then have less: "k \<le> 0 \<longleftrightarrow> False"
     by simp
   define n where "n = nat_of_integer (k - 1)"
   with True have k: "k - 1 = of_nat n" "k = of_nat (Suc n)"
     by simp_all
   show ?thesis unfolding less Let_def k(1) unfolding k(2) exists_upto_of_nat
     using less_Suc_eq by auto
 qed
 
 lemma [code]:
   "IArray.exists p as \<longleftrightarrow> exists_upto p (length' as) as"
   including integer.lifting by (simp, transfer)
    (auto, metis in_set_conv_nth less_imp_of_nat_less nat_int of_nat_0_le_iff)
 
 end
 
 
 subsection \<open>Code Generation for SML\<close>
 
 text \<open>Note that arrays cannot be printed directly but only by turning them into
 lists first. Arrays could be converted back into lists for printing if they
 were wrapped up in an additional constructor.\<close>
 
 code_reserved SML Vector
 
 code_printing
   type_constructor iarray \<rightharpoonup> (SML) "_ Vector.vector"
 | constant IArray \<rightharpoonup> (SML) "Vector.fromList"
 | constant IArray.all \<rightharpoonup> (SML) "Vector.all"
 | constant IArray.exists \<rightharpoonup> (SML) "Vector.exists"
 | constant IArray.tabulate \<rightharpoonup> (SML) "Vector.tabulate"
 | constant IArray.sub' \<rightharpoonup> (SML) "Vector.sub"
 | constant IArray.length' \<rightharpoonup> (SML) "Vector.length"
 
 
 subsection \<open>Code Generation for Haskell\<close>
 
 text \<open>We map \<^typ>\<open>'a iarray\<close>s in Isabelle/HOL to \<open>Data.Array.IArray.array\<close>
   in Haskell.  Performance mapping to \<open>Data.Array.Unboxed.Array\<close> and
   \<open>Data.Array.Array\<close> is similar.\<close>
 
 code_printing
   code_module "IArray" \<rightharpoonup> (Haskell) \<open>
 module IArray(IArray, tabulate, of_list, sub, length) where {
 
   import Prelude (Bool(True, False), not, Maybe(Nothing, Just),
     Integer, (+), (-), (<), fromInteger, toInteger, map, seq, (.));
   import qualified Prelude;
   import qualified Data.Array.IArray;
   import qualified Data.Array.Base;
   import qualified Data.Ix;
 
   newtype IArray e = IArray (Data.Array.IArray.Array Integer e);
 
   tabulate :: (Integer, (Integer -> e)) -> IArray e;
   tabulate (k, f) = IArray (Data.Array.IArray.array (0, k - 1) (map (\i -> let fi = f i in fi `seq` (i, fi)) [0..k - 1]));
 
   of_list :: [e] -> IArray e;
   of_list l = IArray (Data.Array.IArray.listArray (0, (toInteger . Prelude.length) l - 1) l);
 
   sub :: (IArray e, Integer) -> e;
   sub (IArray v, i) = v `Data.Array.Base.unsafeAt` fromInteger i;
 
   length :: IArray e -> Integer;
   length (IArray v) = toInteger (Data.Ix.rangeSize (Data.Array.IArray.bounds v));
 
 }\<close> for type_constructor iarray constant IArray IArray.tabulate IArray.sub' IArray.length'
 
 code_reserved Haskell IArray_Impl
 
 code_printing
   type_constructor iarray \<rightharpoonup> (Haskell) "IArray.IArray _"
 | constant IArray \<rightharpoonup> (Haskell) "IArray.of'_list"
 | constant IArray.tabulate \<rightharpoonup> (Haskell) "IArray.tabulate"
 | constant IArray.sub' \<rightharpoonup> (Haskell)  "IArray.sub"
 | constant IArray.length' \<rightharpoonup> (Haskell) "IArray.length"
 
 end
diff --git a/src/HOL/SMT.thy b/src/HOL/SMT.thy
--- a/src/HOL/SMT.thy
+++ b/src/HOL/SMT.thy
@@ -1,898 +1,898 @@
 (*  Title:      HOL/SMT.thy
     Author:     Sascha Boehme, TU Muenchen
     Author:     Jasmin Blanchette, VU Amsterdam
 *)
 
 section \<open>Bindings to Satisfiability Modulo Theories (SMT) solvers based on SMT-LIB 2\<close>
 
 theory SMT
   imports Divides Numeral_Simprocs
   keywords "smt_status" :: diag
 begin
 
 subsection \<open>A skolemization tactic and proof method\<close>
 
 lemma choices:
   "\<And>Q. \<forall>x. \<exists>y ya. Q x y ya \<Longrightarrow> \<exists>f fa. \<forall>x. Q x (f x) (fa x)"
   "\<And>Q. \<forall>x. \<exists>y ya yb. Q x y ya yb \<Longrightarrow> \<exists>f fa fb. \<forall>x. Q x (f x) (fa x) (fb x)"
   "\<And>Q. \<forall>x. \<exists>y ya yb yc. Q x y ya yb yc \<Longrightarrow> \<exists>f fa fb fc. \<forall>x. Q x (f x) (fa x) (fb x) (fc x)"
   "\<And>Q. \<forall>x. \<exists>y ya yb yc yd. Q x y ya yb yc yd \<Longrightarrow>
      \<exists>f fa fb fc fd. \<forall>x. Q x (f x) (fa x) (fb x) (fc x) (fd x)"
   "\<And>Q. \<forall>x. \<exists>y ya yb yc yd ye. Q x y ya yb yc yd ye \<Longrightarrow>
      \<exists>f fa fb fc fd fe. \<forall>x. Q x (f x) (fa x) (fb x) (fc x) (fd x) (fe x)"
   "\<And>Q. \<forall>x. \<exists>y ya yb yc yd ye yf. Q x y ya yb yc yd ye yf \<Longrightarrow>
      \<exists>f fa fb fc fd fe ff. \<forall>x. Q x (f x) (fa x) (fb x) (fc x) (fd x) (fe x) (ff x)"
   "\<And>Q. \<forall>x. \<exists>y ya yb yc yd ye yf yg. Q x y ya yb yc yd ye yf yg \<Longrightarrow>
      \<exists>f fa fb fc fd fe ff fg. \<forall>x. Q x (f x) (fa x) (fb x) (fc x) (fd x) (fe x) (ff x) (fg x)"
   by metis+
 
 lemma bchoices:
   "\<And>Q. \<forall>x \<in> S. \<exists>y ya. Q x y ya \<Longrightarrow> \<exists>f fa. \<forall>x \<in> S. Q x (f x) (fa x)"
   "\<And>Q. \<forall>x \<in> S. \<exists>y ya yb. Q x y ya yb \<Longrightarrow> \<exists>f fa fb. \<forall>x \<in> S. Q x (f x) (fa x) (fb x)"
   "\<And>Q. \<forall>x \<in> S. \<exists>y ya yb yc. Q x y ya yb yc \<Longrightarrow> \<exists>f fa fb fc. \<forall>x \<in> S. Q x (f x) (fa x) (fb x) (fc x)"
   "\<And>Q. \<forall>x \<in> S. \<exists>y ya yb yc yd. Q x y ya yb yc yd \<Longrightarrow>
     \<exists>f fa fb fc fd. \<forall>x \<in> S. Q x (f x) (fa x) (fb x) (fc x) (fd x)"
   "\<And>Q. \<forall>x \<in> S. \<exists>y ya yb yc yd ye. Q x y ya yb yc yd ye \<Longrightarrow>
     \<exists>f fa fb fc fd fe. \<forall>x \<in> S. Q x (f x) (fa x) (fb x) (fc x) (fd x) (fe x)"
   "\<And>Q. \<forall>x \<in> S. \<exists>y ya yb yc yd ye yf. Q x y ya yb yc yd ye yf \<Longrightarrow>
     \<exists>f fa fb fc fd fe ff. \<forall>x \<in> S. Q x (f x) (fa x) (fb x) (fc x) (fd x) (fe x) (ff x)"
   "\<And>Q. \<forall>x \<in> S. \<exists>y ya yb yc yd ye yf yg. Q x y ya yb yc yd ye yf yg \<Longrightarrow>
     \<exists>f fa fb fc fd fe ff fg. \<forall>x \<in> S. Q x (f x) (fa x) (fb x) (fc x) (fd x) (fe x) (ff x) (fg x)"
   by metis+
 
 ML \<open>
 fun moura_tac ctxt =
   Atomize_Elim.atomize_elim_tac ctxt THEN'
   SELECT_GOAL (Clasimp.auto_tac (ctxt addSIs @{thms choice choices bchoice bchoices}) THEN
     ALLGOALS (Metis_Tactic.metis_tac (take 1 ATP_Proof_Reconstruct.partial_type_encs)
         ATP_Proof_Reconstruct.default_metis_lam_trans ctxt [] ORELSE'
       blast_tac ctxt))
 \<close>
 
 method_setup moura = \<open>
   Scan.succeed (SIMPLE_METHOD' o moura_tac)
 \<close> "solve skolemization goals, especially those arising from Z3 proofs"
 
 hide_fact (open) choices bchoices
 
 
 subsection \<open>Triggers for quantifier instantiation\<close>
 
 text \<open>
 Some SMT solvers support patterns as a quantifier instantiation
 heuristics. Patterns may either be positive terms (tagged by "pat")
 triggering quantifier instantiations -- when the solver finds a
 term matching a positive pattern, it instantiates the corresponding
 quantifier accordingly -- or negative terms (tagged by "nopat")
 inhibiting quantifier instantiations. A list of patterns
 of the same kind is called a multipattern, and all patterns in a
 multipattern are considered conjunctively for quantifier instantiation.
 A list of multipatterns is called a trigger, and their multipatterns
 act disjunctively during quantifier instantiation. Each multipattern
 should mention at least all quantified variables of the preceding
 quantifier block.
 \<close>
 
 typedecl 'a symb_list
 
 consts
   Symb_Nil :: "'a symb_list"
   Symb_Cons :: "'a \<Rightarrow> 'a symb_list \<Rightarrow> 'a symb_list"
 
 typedecl pattern
 
 consts
   pat :: "'a \<Rightarrow> pattern"
   nopat :: "'a \<Rightarrow> pattern"
 
 definition trigger :: "pattern symb_list symb_list \<Rightarrow> bool \<Rightarrow> bool" where
   "trigger _ P = P"
 
 
 subsection \<open>Higher-order encoding\<close>
 
 text \<open>
 Application is made explicit for constants occurring with varying
 numbers of arguments. This is achieved by the introduction of the
 following constant.
 \<close>
 
 definition fun_app :: "'a \<Rightarrow> 'a" where "fun_app f = f"
 
 text \<open>
 Some solvers support a theory of arrays which can be used to encode
 higher-order functions. The following set of lemmas specifies the
 properties of such (extensional) arrays.
 \<close>
 
 lemmas array_rules = ext fun_upd_apply fun_upd_same fun_upd_other  fun_upd_upd fun_app_def
 
 
 subsection \<open>Normalization\<close>
 
 lemma case_bool_if[abs_def]: "case_bool x y P = (if P then x else y)"
   by simp
 
 lemmas Ex1_def_raw = Ex1_def[abs_def]
 lemmas Ball_def_raw = Ball_def[abs_def]
 lemmas Bex_def_raw = Bex_def[abs_def]
 lemmas abs_if_raw = abs_if[abs_def]
 lemmas min_def_raw = min_def[abs_def]
 lemmas max_def_raw = max_def[abs_def]
 
 lemma nat_zero_as_int:
   "0 = nat 0"
   by simp
 
 lemma nat_one_as_int:
   "1 = nat 1"
   by simp
 
 lemma nat_numeral_as_int: "numeral = (\<lambda>i. nat (numeral i))" by simp
 lemma nat_less_as_int: "(<) = (\<lambda>a b. int a < int b)" by simp
 lemma nat_leq_as_int: "(\<le>) = (\<lambda>a b. int a \<le> int b)" by simp
 lemma Suc_as_int: "Suc = (\<lambda>a. nat (int a + 1))" by (rule ext) simp
 lemma nat_plus_as_int: "(+) = (\<lambda>a b. nat (int a + int b))" by (rule ext)+ simp
 lemma nat_minus_as_int: "(-) = (\<lambda>a b. nat (int a - int b))" by (rule ext)+ simp
 lemma nat_times_as_int: "(*) = (\<lambda>a b. nat (int a * int b))" by (simp add: nat_mult_distrib)
 lemma nat_div_as_int: "(div) = (\<lambda>a b. nat (int a div int b))" by (simp add: nat_div_distrib)
 lemma nat_mod_as_int: "(mod) = (\<lambda>a b. nat (int a mod int b))" by (simp add: nat_mod_distrib)
 
 lemma int_Suc: "int (Suc n) = int n + 1" by simp
 lemma int_plus: "int (n + m) = int n + int m" by (rule of_nat_add)
 lemma int_minus: "int (n - m) = int (nat (int n - int m))" by auto
 
 lemma nat_int_comparison:
   fixes a b :: nat
   shows "(a = b) = (int a = int b)"
     and "(a < b) = (int a < int b)"
     and "(a \<le> b) = (int a \<le> int b)"
   by simp_all
 
 lemma int_ops:
   fixes a b :: nat
   shows "int 0 = 0"
     and "int 1 = 1"
     and "int (numeral n) = numeral n"
     and "int (Suc a) = int a + 1"
     and "int (a + b) = int a + int b"
     and "int (a - b) = (if int a < int b then 0 else int a - int b)"
     and "int (a * b) = int a * int b"
     and "int (a div b) = int a div int b"
     and "int (a mod b) = int a mod int b"
   by (auto intro: zdiv_int zmod_int)
 
 lemma int_if:
   fixes a b :: nat
   shows "int (if P then a else b) = (if P then int a else int b)"
   by simp
 
 
 subsection \<open>Integer division and modulo for Z3\<close>
 
 text \<open>
 The following Z3-inspired definitions are overspecified for the case where \<open>l = 0\<close>. This
 Schönheitsfehler is corrected in the \<open>div_as_z3div\<close> and \<open>mod_as_z3mod\<close> theorems.
 \<close>
 
 definition z3div :: "int \<Rightarrow> int \<Rightarrow> int" where
   "z3div k l = (if l \<ge> 0 then k div l else - (k div - l))"
 
 definition z3mod :: "int \<Rightarrow> int \<Rightarrow> int" where
   "z3mod k l = k mod (if l \<ge> 0 then l else - l)"
 
 lemma div_as_z3div:
   "\<forall>k l. k div l = (if l = 0 then 0 else if l > 0 then z3div k l else z3div (- k) (- l))"
   by (simp add: z3div_def)
 
 lemma mod_as_z3mod:
   "\<forall>k l. k mod l = (if l = 0 then k else if l > 0 then z3mod k l else - z3mod (- k) (- l))"
   by (simp add: z3mod_def)
 
 
 subsection \<open>Extra theorems for veriT reconstruction\<close>
 
 lemma verit_sko_forall: \<open>(\<forall>x. P x) \<longleftrightarrow> P (SOME x. \<not>P x)\<close>
   using someI[of \<open>\<lambda>x. \<not>P x\<close>]
   by auto
 
 lemma verit_sko_forall': \<open>P (SOME x. \<not>P x) = A \<Longrightarrow> (\<forall>x. P x) = A\<close>
   by (subst verit_sko_forall)
 
 lemma verit_sko_forall'': \<open>B = A \<Longrightarrow> (SOME x. P x) = A \<equiv> (SOME x. P x) = B\<close>
   by auto
 
 lemma verit_sko_forall_indirect: \<open>x = (SOME x. \<not>P x) \<Longrightarrow> (\<forall>x. P x) \<longleftrightarrow> P x\<close>
   using someI[of \<open>\<lambda>x. \<not>P x\<close>]
   by auto
 
 lemma verit_sko_forall_indirect2:
     \<open>x = (SOME x. \<not>P x) \<Longrightarrow> (\<And>x :: 'a. (P x = P' x)) \<Longrightarrow>(\<forall>x. P' x) \<longleftrightarrow> P x\<close>
   using someI[of \<open>\<lambda>x. \<not>P x\<close>]
   by auto
 
 lemma verit_sko_ex: \<open>(\<exists>x. P x) \<longleftrightarrow> P (SOME x. P x)\<close>
   using someI[of \<open>\<lambda>x. P x\<close>]
   by auto
 
 lemma verit_sko_ex': \<open>P (SOME x. P x) = A \<Longrightarrow> (\<exists>x. P x) = A\<close>
   by (subst verit_sko_ex)
 
 lemma verit_sko_ex_indirect: \<open>x = (SOME x. P x) \<Longrightarrow> (\<exists>x. P x) \<longleftrightarrow> P x\<close>
   using someI[of \<open>\<lambda>x. P x\<close>]
   by auto
 
 lemma verit_sko_ex_indirect2: \<open>x = (SOME x. P x) \<Longrightarrow> (\<And>x. P x = P' x) \<Longrightarrow> (\<exists>x. P' x) \<longleftrightarrow> P x\<close>
   using someI[of \<open>\<lambda>x. P x\<close>]
   by auto
 
 lemma verit_Pure_trans:
   \<open>P \<equiv> Q \<Longrightarrow> Q \<Longrightarrow> P\<close>
   by auto
 
 lemma verit_if_cong:
   assumes \<open>b \<equiv> c\<close>
     and \<open>c \<Longrightarrow> x \<equiv> u\<close>
     and \<open>\<not> c \<Longrightarrow> y \<equiv> v\<close>
   shows \<open>(if b then x else y) \<equiv> (if c then u else v)\<close>
   using assms if_cong[of b c x u] by auto
 
 lemma verit_if_weak_cong':
   \<open>b \<equiv> c \<Longrightarrow> (if b then x else y) \<equiv> (if c then x else y)\<close>
   by auto
 
 lemma verit_or_neg:
    \<open>(A \<Longrightarrow> B) \<Longrightarrow> B \<or> \<not>A\<close>
    \<open>(\<not>A \<Longrightarrow> B) \<Longrightarrow> B \<or> A\<close>
   by auto
 
 lemma verit_subst_bool: \<open>P \<Longrightarrow> f True \<Longrightarrow> f P\<close>
   by auto
 
 lemma verit_and_pos:
   \<open>(a \<Longrightarrow> \<not>(b \<and> c) \<or> A) \<Longrightarrow> \<not>(a \<and> b \<and> c) \<or> A\<close>
   \<open>(a \<Longrightarrow> b \<Longrightarrow> A) \<Longrightarrow> \<not>(a \<and> b) \<or> A\<close>
   \<open>(a \<Longrightarrow> A) \<Longrightarrow> \<not>a \<or> A\<close>
   \<open>(\<not>a \<Longrightarrow> A) \<Longrightarrow> a \<or> A\<close>
   by blast+
 
 lemma verit_or_pos:
    \<open>A \<and> A' \<Longrightarrow> (c \<and> A) \<or> (\<not>c \<and> A')\<close>
    \<open>A \<and> A' \<Longrightarrow> (\<not>c \<and> A) \<or> (c \<and> A')\<close>
   by blast+
 
 
 lemma verit_la_generic:
   \<open>(a::int) \<le> x \<or> a = x \<or> a \<ge> x\<close>
   by linarith
 
 lemma verit_bfun_elim:
   \<open>(if b then P True else P False) = P b\<close>
   \<open>(\<forall>b. P' b) = (P' False \<and> P' True)\<close>
   \<open>(\<exists>b. P' b) = (P' False \<or> P' True)\<close>
   by (cases b) (auto simp: all_bool_eq ex_bool_eq)
 
 lemma verit_eq_true_simplify:
   \<open>(P = True) \<equiv> P\<close>
   by auto
 
 lemma verit_and_neg:
   \<open>(a \<Longrightarrow> \<not>b \<or> A) \<Longrightarrow> \<not>(a \<and> b) \<or> A\<close>
   \<open>(a \<Longrightarrow> A) \<Longrightarrow> \<not>a \<or> A\<close>
   \<open>(\<not>a \<Longrightarrow> A) \<Longrightarrow> a \<or> A\<close>
   by blast+
 
 lemma verit_forall_inst:
   \<open>A \<longleftrightarrow> B \<Longrightarrow> \<not>A \<or> B\<close>
   \<open>\<not>A \<longleftrightarrow> B \<Longrightarrow> A \<or> B\<close>
   \<open>A \<longleftrightarrow> B \<Longrightarrow> \<not>B \<or> A\<close>
   \<open>A \<longleftrightarrow> \<not>B \<Longrightarrow> B \<or> A\<close>
   \<open>A \<longrightarrow> B \<Longrightarrow> \<not>A \<or> B\<close>
   \<open>\<not>A \<longrightarrow> B \<Longrightarrow> A \<or> B\<close>
   by blast+
 
 lemma verit_eq_transitive:
   \<open>A = B \<Longrightarrow> B = C \<Longrightarrow> A = C\<close>
   \<open>A = B \<Longrightarrow> C = B \<Longrightarrow> A = C\<close>
   \<open>B = A \<Longrightarrow> B = C \<Longrightarrow> A = C\<close>
   \<open>B = A \<Longrightarrow> C = B \<Longrightarrow> A = C\<close>
   by auto
 
 lemma verit_bool_simplify:
   \<open>\<not>(P \<longrightarrow> Q) \<longleftrightarrow> P \<and> \<not>Q\<close>
   \<open>\<not>(P \<or> Q) \<longleftrightarrow> \<not>P \<and> \<not>Q\<close>
   \<open>\<not>(P \<and> Q) \<longleftrightarrow> \<not>P \<or> \<not>Q\<close>
   \<open>(P \<longrightarrow> (Q \<longrightarrow> R)) \<longleftrightarrow> ((P \<and> Q) \<longrightarrow> R)\<close>
   \<open>((P \<longrightarrow> Q) \<longrightarrow> Q) \<longleftrightarrow> P \<or> Q\<close>
   \<open>(Q \<longleftrightarrow> (P \<or> Q)) \<longleftrightarrow> (P \<longrightarrow> Q)\<close> \<comment> \<open>This rule was inverted\<close>
   \<open>P \<and> (P \<longrightarrow> Q) \<longleftrightarrow> P \<and> Q\<close>
   \<open>(P \<longrightarrow> Q) \<and> P \<longleftrightarrow> P \<and> Q\<close>
  (* \<comment>\<open>Additional rules:\<close>
   *  \<open>((P \<longrightarrow> Q) \<longrightarrow> P) \<longleftrightarrow> P\<close>
   *  \<open>((P \<longrightarrow> Q) \<longrightarrow> Q) \<longleftrightarrow> P \<or> Q\<close>
   *  \<open>(P \<longrightarrow> Q) \<or> P\<close> *)
   unfolding not_imp imp_conjL
   by auto
 
 text \<open>We need the last equation for \<^term>\<open>\<not>(\<forall>a b. \<not>P a b)\<close>\<close>
 lemma verit_connective_def: \<comment> \<open>the definition of XOR is missing
   as the operator is not generated by Isabelle\<close>
   \<open>(A = B) \<longleftrightarrow> ((A \<longrightarrow> B) \<and> (B \<longrightarrow> A))\<close>
   \<open>(If A B C) = ((A \<longrightarrow> B) \<and> (\<not>A \<longrightarrow> C))\<close>
   \<open>(\<exists>x. P x) \<longleftrightarrow> \<not>(\<forall>x. \<not>P x)\<close>
   \<open>\<not>(\<exists>x. P x) \<longleftrightarrow> (\<forall>x. \<not>P x)\<close>
   by auto
 
 lemma verit_ite_simplify:
   \<open>(If True B C) = B\<close>
   \<open>(If False B C) = C\<close>
   \<open>(If A' B B) = B\<close>
   \<open>(If (\<not>A') B C) = (If A' C B)\<close>
   \<open>(If c (If c A B) C) = (If c A C)\<close>
   \<open>(If c C (If c A B)) = (If c C B)\<close>
   \<open>(If A' True False) = A'\<close>
   \<open>(If A' False True) \<longleftrightarrow> \<not>A'\<close>
   \<open>(If A' True B') \<longleftrightarrow> A'\<or>B'\<close>
   \<open>(If A' B' False) \<longleftrightarrow> A'\<and>B'\<close>
   \<open>(If A' False B') \<longleftrightarrow> \<not>A'\<and>B'\<close>
   \<open>(If A' B' True) \<longleftrightarrow> \<not>A'\<or>B'\<close>
   \<open>x \<and> True \<longleftrightarrow> x\<close>
   \<open>x \<or> False \<longleftrightarrow> x\<close>
   for B C :: 'a and A' B' C' :: bool
   by auto
 
 lemma verit_and_simplify1:
   \<open>True \<and> b \<longleftrightarrow> b\<close> \<open>b \<and> True \<longleftrightarrow> b\<close>
   \<open>False \<and> b \<longleftrightarrow> False\<close> \<open>b \<and> False \<longleftrightarrow> False\<close>
   \<open>(c \<and> \<not>c) \<longleftrightarrow> False\<close> \<open>(\<not>c \<and> c) \<longleftrightarrow> False\<close>
   \<open>\<not>\<not>a = a\<close>
   by auto
 
 lemmas verit_and_simplify = conj_ac de_Morgan_conj disj_not1
 
 
 lemma verit_or_simplify_1:
   \<open>False \<or> b \<longleftrightarrow> b\<close> \<open>b \<or> False \<longleftrightarrow> b\<close>
   \<open>b \<or> \<not>b\<close>
   \<open>\<not>b \<or> b\<close>
   by auto
 
 lemmas verit_or_simplify = disj_ac
 
 lemma verit_not_simplify:
   \<open>\<not> \<not>b \<longleftrightarrow> b\<close> \<open>\<not>True \<longleftrightarrow> False\<close> \<open>\<not>False \<longleftrightarrow> True\<close>
   by auto
 
 
 lemma verit_implies_simplify:
   \<open>(\<not>a \<longrightarrow> \<not>b) \<longleftrightarrow> (b \<longrightarrow> a)\<close>
   \<open>(False \<longrightarrow> a) \<longleftrightarrow> True\<close>
   \<open>(a \<longrightarrow> True) \<longleftrightarrow> True\<close>
   \<open>(True \<longrightarrow> a) \<longleftrightarrow> a\<close>
   \<open>(a \<longrightarrow> False) \<longleftrightarrow> \<not>a\<close>
   \<open>(a \<longrightarrow> a) \<longleftrightarrow> True\<close>
   \<open>(\<not>a \<longrightarrow> a) \<longleftrightarrow> a\<close>
   \<open>(a \<longrightarrow> \<not>a) \<longleftrightarrow> \<not>a\<close>
   \<open>((a \<longrightarrow> b) \<longrightarrow> b) \<longleftrightarrow> a \<or> b\<close>
   by auto
 
 lemma verit_equiv_simplify:
   \<open>((\<not>a) = (\<not>b)) \<longleftrightarrow> (a = b)\<close>
   \<open>(a = a) \<longleftrightarrow> True\<close>
   \<open>(a = (\<not>a)) \<longleftrightarrow> False\<close>
   \<open>((\<not>a) = a) \<longleftrightarrow> False\<close>
   \<open>(True = a) \<longleftrightarrow> a\<close>
   \<open>(a = True) \<longleftrightarrow> a\<close>
   \<open>(False = a) \<longleftrightarrow> \<not>a\<close>
   \<open>(a = False) \<longleftrightarrow> \<not>a\<close>
   \<open>\<not>\<not>a \<longleftrightarrow> a\<close>
   \<open>(\<not> False) = True\<close>
   for a b :: bool
   by auto
 
 lemmas verit_eq_simplify =
   semiring_char_0_class.eq_numeral_simps eq_refl zero_neq_one num.simps
   neg_equal_zero equal_neg_zero one_neq_zero neg_equal_iff_equal
 
 lemma verit_minus_simplify:
   \<open>(a :: 'a :: cancel_comm_monoid_add) - a = 0\<close>
   \<open>(a :: 'a :: cancel_comm_monoid_add) - 0 = a\<close>
   \<open>0 - (b :: 'b :: {group_add}) = -b\<close>
   \<open>- (- (b :: 'b :: group_add)) = b\<close>
   by auto
 
 lemma verit_sum_simplify:
   \<open>(a :: 'a :: cancel_comm_monoid_add) + 0 = a\<close>
   by auto
 
 lemmas verit_prod_simplify =
 (* already included:
    mult_zero_class.mult_zero_right
    mult_zero_class.mult_zero_left *)
    mult_1
    mult_1_right
 
 lemma verit_comp_simplify1:
   \<open>(a :: 'a ::order) < a \<longleftrightarrow> False\<close>
   \<open>a \<le> a\<close>
   \<open>\<not>(b' \<le> a') \<longleftrightarrow> (a' :: 'b :: linorder) < b'\<close>
   by auto
 
 lemmas verit_comp_simplify =
   verit_comp_simplify1
   le_numeral_simps
   le_num_simps
   less_numeral_simps
   less_num_simps
   zero_less_one
   zero_le_one
   less_neg_numeral_simps
 
 lemma verit_la_disequality:
   \<open>(a :: 'a ::linorder) = b \<or> \<not>a \<le> b \<or> \<not>b \<le> a\<close>
   by auto
 
 context
 begin
 
 text \<open>For the reconstruction, we need to keep the order of the arguments.\<close>
 
 named_theorems smt_arith_multiplication \<open>Theorems to reconstruct arithmetic theorems.\<close>
 
 named_theorems smt_arith_combine \<open>Theorems to reconstruct arithmetic theorems.\<close>
 
 named_theorems smt_arith_simplify \<open>Theorems to combine theorems in the LA procedure\<close>
 
 lemmas [smt_arith_simplify] =
     div_add dvd_numeral_simp divmod_steps less_num_simps le_num_simps if_True if_False divmod_cancel
-    dvd_mult dvd_mult2 less_irrefl prod.case numeral_plus_one divmod_step_eq order.refl le_zero_eq
+    dvd_mult dvd_mult2 less_irrefl prod.case numeral_plus_one divmod_step_def order.refl le_zero_eq
     le_numeral_simps less_numeral_simps mult.right_neutral simp_thms divides_aux_eq
     mult_nonneg_nonneg dvd_imp_mod_0 dvd_add zero_less_one mod_mult_self4 numeral_mod_numeral
     divmod_trivial prod.sel mult.left_neutral div_pos_pos_trivial arith_simps div_add div_mult_self1
     add_le_cancel_left add_le_same_cancel2 not_one_le_zero le_numeral_simps add_le_same_cancel1
     zero_neq_one zero_le_one le_num_simps add_Suc mod_div_trivial nat.distinct mult_minus_right
     add.inverse_inverse distrib_left_numeral mult_num_simps numeral_times_numeral add_num_simps
     divmod_steps rel_simps if_True if_False numeral_div_numeral divmod_cancel prod.case
-    add_num_simps one_plus_numeral fst_conv divmod_step_eq arith_simps sub_num_simps dbl_inc_simps
+    add_num_simps one_plus_numeral fst_conv arith_simps sub_num_simps dbl_inc_simps
     dbl_simps mult_1 add_le_cancel_right left_diff_distrib_numeral add_uminus_conv_diff zero_neq_one
     zero_le_one One_nat_def add_Suc mod_div_trivial nat.distinct of_int_1 numerals numeral_One
     of_int_numeral add_uminus_conv_diff zle_diff1_eq add_less_same_cancel2 minus_add_distrib
     add_uminus_conv_diff mult.left_neutral semiring_class.distrib_right
     add_diff_cancel_left' add_diff_eq ring_distribs mult_minus_left minus_diff_eq
 
 lemma [smt_arith_simplify]:
   \<open>\<not> (a' :: 'a :: linorder) < b' \<longleftrightarrow> b' \<le> a'\<close>
   \<open>\<not> (a' :: 'a :: linorder) \<le> b' \<longleftrightarrow> b' < a'\<close>
   \<open>(c::int) mod Numeral1 = 0\<close>
   \<open>(a::nat) mod Numeral1 = 0\<close>
   \<open>(c::int) div Numeral1 = c\<close>
   \<open>a div Numeral1 = a\<close>
   \<open>(c::int) mod 1 = 0\<close>
   \<open>a mod 1 = 0\<close>
   \<open>(c::int) div 1 = c\<close>
   \<open>a div 1 = a\<close>
   \<open>\<not>(a' \<noteq> b') \<longleftrightarrow> a' = b'\<close>
   by auto
 
 
 lemma div_mod_decomp: "A = (A div n) * n + (A mod n)" for A :: nat
   by auto
 
 lemma div_less_mono:
   fixes A B :: nat
   assumes "A < B" "0 < n" and
     mod: "A mod n = 0""B mod n = 0"
   shows "(A div n) < (B div n)"
 proof -
   show ?thesis
     using assms(1)
     apply (subst (asm) div_mod_decomp[of "A" n])
     apply (subst (asm) div_mod_decomp[of "B" n])
     unfolding mod
     by (use assms(2,3) in \<open>auto simp: ac_simps\<close>)
 qed
 
 lemma verit_le_mono_div:
   fixes A B :: nat
   assumes "A < B" "0 < n"
   shows "(A div n) + (if B mod n = 0 then 1 else 0) \<le> (B div n)"
   by (auto simp: ac_simps Suc_leI assms less_mult_imp_div_less div_le_mono less_imp_le_nat)
 
 lemmas [smt_arith_multiplication] =
   verit_le_mono_div[THEN mult_le_mono1, unfolded add_mult_distrib]
   div_le_mono[THEN mult_le_mono2, unfolded add_mult_distrib]
 
 lemma div_mod_decomp_int: "A = (A div n) * n + (A mod n)" for A :: int
   by auto
 
 lemma zdiv_mono_strict:
   fixes A B :: int
   assumes "A < B" "0 < n" and
     mod: "A mod n = 0""B mod n = 0"
   shows "(A div n) < (B div n)"
 proof -
   show ?thesis
     using assms(1)
     apply (subst (asm) div_mod_decomp_int[of A n])
     apply (subst (asm) div_mod_decomp_int[of B n])
     unfolding mod
     by (use assms(2,3) in \<open>auto simp: ac_simps\<close>)
 qed
 
 lemma verit_le_mono_div_int:
   fixes A B :: int
   assumes "A < B" "0 < n"
   shows "(A div n) + (if B mod n = 0 then 1 else 0) \<le> (B div n)"
 proof -
   have f2: "B div n = A div n \<or> A div n < B div n"
     by (metis (no_types) assms less_le zdiv_mono1)
   have "B div n \<noteq> A div n \<or> B mod n \<noteq> 0"
     using assms(1) by (metis Groups.add_ac(2) assms(2) eucl_rel_int eucl_rel_int_iff
       group_cancel.rule0 le_add_same_cancel2 not_le)
   then have "B mod n = 0 \<longrightarrow> A div n + (if B mod n = 0 then 1 else 0) \<le> B div n"
     using f2 by (auto dest: zless_imp_add1_zle)
   then show ?thesis
     using assms zdiv_mono1 by auto
 qed
 
 
 lemma verit_less_mono_div_int2:
   fixes A B :: int
   assumes "A \<le> B" "0 < -n"
   shows "(A div n) \<ge> (B div n)"
   using assms(1) assms(2) zdiv_mono1_neg by auto
 
 lemmas [smt_arith_multiplication] =
   verit_le_mono_div_int[THEN mult_left_mono, unfolded int_distrib]
   zdiv_mono1[THEN mult_left_mono, unfolded int_distrib]
 
 lemmas [smt_arith_multiplication] =
   arg_cong[of _ _ \<open>\<lambda>a :: nat. a div n * p\<close> for n p :: nat, THEN sym]
   arg_cong[of _ _ \<open>\<lambda>a :: int. a div n * p\<close> for n p :: int, THEN sym]
 
 lemma [smt_arith_combine]:
   "a < b \<Longrightarrow> c < d \<Longrightarrow> a + c + 2 \<le> b + d"
   "a < b \<Longrightarrow> c \<le> d \<Longrightarrow> a + c + 1 \<le> b + d"
   "a \<le> b \<Longrightarrow> c < d \<Longrightarrow> a + c + 1 \<le> b + d" for a b c :: int
   by auto
 
 lemma [smt_arith_combine]:
   "a < b \<Longrightarrow> c < d \<Longrightarrow> a + c + 2 \<le> b + d"
   "a < b \<Longrightarrow> c \<le> d \<Longrightarrow> a + c + 1 \<le> b + d"
   "a \<le> b \<Longrightarrow> c < d \<Longrightarrow> a + c + 1 \<le> b + d" for a b c :: nat
   by auto
 
 lemmas [smt_arith_combine] =
   add_strict_mono
   add_less_le_mono
   add_mono
   add_le_less_mono
 
 lemma [smt_arith_combine]:
   \<open>m < n \<Longrightarrow> c = d \<Longrightarrow> m + c < n + d\<close>
   \<open>m \<le> n \<Longrightarrow> c = d \<Longrightarrow> m + c \<le> n + d\<close>
   \<open>c = d \<Longrightarrow> m < n \<Longrightarrow> m + c < n + d\<close>
   \<open>c = d \<Longrightarrow> m \<le> n \<Longrightarrow> m + c \<le> n + d\<close>
   for m :: \<open>'a :: ordered_cancel_ab_semigroup_add\<close>
   by (auto intro: ordered_cancel_ab_semigroup_add_class.add_strict_right_mono
     ordered_ab_semigroup_add_class.add_right_mono)
 
 lemma verit_negate_coefficient:
   \<open>a \<le> (b :: 'a :: {ordered_ab_group_add}) \<Longrightarrow> -a \<ge> -b\<close>
   \<open>a < b \<Longrightarrow> -a > -b\<close>
   \<open>a = b \<Longrightarrow> -a = -b\<close>
   by auto
 
 end
 
 lemma verit_ite_intro:
   \<open>(if a then P (if a then a' else b') else Q) \<longleftrightarrow> (if a then P a' else Q)\<close>
   \<open>(if a then P' else Q' (if a then a' else b')) \<longleftrightarrow> (if a then P' else Q' b')\<close>
   \<open>A = f (if a then R else S) \<longleftrightarrow> (if a then A = f R else A = f S)\<close>
   by auto
 
 lemma verit_ite_if_cong:
   fixes x y :: bool
   assumes "b=c"
     and "c \<equiv> True \<Longrightarrow> x = u"
     and "c \<equiv> False \<Longrightarrow> y = v"
   shows "(if b then x else y) \<equiv> (if c then u else v)"
 proof -
   have H: "(if b then x else y) = (if c then u else v)"
     using assms by (auto split: if_splits)
 
   show "(if b then x else y) \<equiv> (if c then u else v)"
     by (subst H) auto
 qed
 
 
 subsection \<open>Setup\<close>
 
 ML_file \<open>Tools/SMT/smt_util.ML\<close>
 ML_file \<open>Tools/SMT/smt_failure.ML\<close>
 ML_file \<open>Tools/SMT/smt_config.ML\<close>
 ML_file \<open>Tools/SMT/smt_builtin.ML\<close>
 ML_file \<open>Tools/SMT/smt_datatypes.ML\<close>
 ML_file \<open>Tools/SMT/smt_normalize.ML\<close>
 ML_file \<open>Tools/SMT/smt_translate.ML\<close>
 ML_file \<open>Tools/SMT/smtlib.ML\<close>
 ML_file \<open>Tools/SMT/smtlib_interface.ML\<close>
 ML_file \<open>Tools/SMT/smtlib_proof.ML\<close>
 ML_file \<open>Tools/SMT/smtlib_isar.ML\<close>
 ML_file \<open>Tools/SMT/z3_proof.ML\<close>
 ML_file \<open>Tools/SMT/z3_isar.ML\<close>
 ML_file \<open>Tools/SMT/smt_solver.ML\<close>
 ML_file \<open>Tools/SMT/cvc_interface.ML\<close>
 ML_file \<open>Tools/SMT/lethe_proof.ML\<close>
 ML_file \<open>Tools/SMT/lethe_isar.ML\<close>
 ML_file \<open>Tools/SMT/lethe_proof_parse.ML\<close>
 ML_file \<open>Tools/SMT/cvc_proof_parse.ML\<close>
 ML_file \<open>Tools/SMT/verit_proof.ML\<close>
 ML_file \<open>Tools/SMT/conj_disj_perm.ML\<close>
 ML_file \<open>Tools/SMT/smt_replay_methods.ML\<close>
 ML_file \<open>Tools/SMT/smt_replay.ML\<close>
 ML_file \<open>Tools/SMT/smt_replay_arith.ML\<close>
 ML_file \<open>Tools/SMT/z3_interface.ML\<close>
 ML_file \<open>Tools/SMT/z3_replay_rules.ML\<close>
 ML_file \<open>Tools/SMT/z3_replay_methods.ML\<close>
 ML_file \<open>Tools/SMT/z3_replay.ML\<close>
 ML_file \<open>Tools/SMT/lethe_replay_methods.ML\<close>
 ML_file \<open>Tools/SMT/verit_replay_methods.ML\<close>
 ML_file \<open>Tools/SMT/verit_replay.ML\<close>
 ML_file \<open>Tools/SMT/smt_systems.ML\<close>
 
 
 subsection \<open>Configuration\<close>
 
 text \<open>
 The current configuration can be printed by the command
 \<open>smt_status\<close>, which shows the values of most options.
 \<close>
 
 
 subsection \<open>General configuration options\<close>
 
 text \<open>
 The option \<open>smt_solver\<close> can be used to change the target SMT
 solver. The possible values can be obtained from the \<open>smt_status\<close>
 command.
 \<close>
 
 declare [[smt_solver = z3]]
 
 text \<open>
 Since SMT solvers are potentially nonterminating, there is a timeout
 (given in seconds) to restrict their runtime.
 \<close>
 
 declare [[smt_timeout = 0]]
 
 text \<open>
 SMT solvers apply randomized heuristics. In case a problem is not
 solvable by an SMT solver, changing the following option might help.
 \<close>
 
 declare [[smt_random_seed = 1]]
 
 text \<open>
 In general, the binding to SMT solvers runs as an oracle, i.e, the SMT
 solvers are fully trusted without additional checks. The following
 option can cause the SMT solver to run in proof-producing mode, giving
 a checkable certificate. This is currently implemented only for veriT and
 Z3.
 \<close>
 
 declare [[smt_oracle = false]]
 
 text \<open>
 Each SMT solver provides several command-line options to tweak its
 behaviour. They can be passed to the solver by setting the following
 options.
 \<close>
 
 declare [[cvc4_options = ""]]
 declare [[cvc5_options = ""]]
 declare [[verit_options = ""]]
 declare [[z3_options = ""]]
 
 text \<open>
 The SMT method provides an inference mechanism to detect simple triggers
 in quantified formulas, which might increase the number of problems
 solvable by SMT solvers (note: triggers guide quantifier instantiations
 in the SMT solver). To turn it on, set the following option.
 \<close>
 
 declare [[smt_infer_triggers = false]]
 
 text \<open>
 Enable the following option to use built-in support for datatypes,
 codatatypes, and records in CVC4 and cvc5. Currently, this is implemented
 only in oracle mode.
 \<close>
 
 declare [[cvc_extensions = false]]
 
 text \<open>
 Enable the following option to use built-in support for div/mod, datatypes,
 and records in Z3. Currently, this is implemented only in oracle mode.
 \<close>
 
 declare [[z3_extensions = false]]
 
 
 subsection \<open>Certificates\<close>
 
 text \<open>
 By setting the option \<open>smt_certificates\<close> to the name of a file,
 all following applications of an SMT solver a cached in that file.
 Any further application of the same SMT solver (using the very same
 configuration) re-uses the cached certificate instead of invoking the
 solver. An empty string disables caching certificates.
 
 The filename should be given as an explicit path. It is good
 practice to use the name of the current theory (with ending
 \<open>.certs\<close> instead of \<open>.thy\<close>) as the certificates file.
 Certificate files should be used at most once in a certain theory context,
 to avoid race conditions with other concurrent accesses.
 \<close>
 
 declare [[smt_certificates = ""]]
 
 text \<open>
 The option \<open>smt_read_only_certificates\<close> controls whether only
 stored certificates should be used or invocation of an SMT solver
 is allowed. When set to \<open>true\<close>, no SMT solver will ever be
 invoked and only the existing certificates found in the configured
 cache are used;  when set to \<open>false\<close> and there is no cached
 certificate for some proposition, then the configured SMT solver is
 invoked.
 \<close>
 
 declare [[smt_read_only_certificates = false]]
 
 
 subsection \<open>Tracing\<close>
 
 text \<open>
 The SMT method, when applied, traces important information. To
 make it entirely silent, set the following option to \<open>false\<close>.
 \<close>
 
 declare [[smt_verbose = true]]
 
 text \<open>
 For tracing the generated problem file given to the SMT solver as
 well as the returned result of the solver, the option
 \<open>smt_trace\<close> should be set to \<open>true\<close>.
 \<close>
 
 declare [[smt_trace = false]]
 
 
 subsection \<open>Schematic rules for Z3 proof reconstruction\<close>
 
 text \<open>
 Several prof rules of Z3 are not very well documented. There are two
 lemma groups which can turn failing Z3 proof reconstruction attempts
 into succeeding ones: the facts in \<open>z3_rule\<close> are tried prior to
 any implemented reconstruction procedure for all uncertain Z3 proof
 rules;  the facts in \<open>z3_simp\<close> are only fed to invocations of
 the simplifier when reconstructing theory-specific proof steps.
 \<close>
 
 lemmas [z3_rule] =
   refl eq_commute conj_commute disj_commute simp_thms nnf_simps
   ring_distribs field_simps times_divide_eq_right times_divide_eq_left
   if_True if_False not_not
   NO_MATCH_def
 
 lemma [z3_rule]:
   "(P \<and> Q) = (\<not> (\<not> P \<or> \<not> Q))"
   "(P \<and> Q) = (\<not> (\<not> Q \<or> \<not> P))"
   "(\<not> P \<and> Q) = (\<not> (P \<or> \<not> Q))"
   "(\<not> P \<and> Q) = (\<not> (\<not> Q \<or> P))"
   "(P \<and> \<not> Q) = (\<not> (\<not> P \<or> Q))"
   "(P \<and> \<not> Q) = (\<not> (Q \<or> \<not> P))"
   "(\<not> P \<and> \<not> Q) = (\<not> (P \<or> Q))"
   "(\<not> P \<and> \<not> Q) = (\<not> (Q \<or> P))"
   by auto
 
 lemma [z3_rule]:
   "(P \<longrightarrow> Q) = (Q \<or> \<not> P)"
   "(\<not> P \<longrightarrow> Q) = (P \<or> Q)"
   "(\<not> P \<longrightarrow> Q) = (Q \<or> P)"
   "(True \<longrightarrow> P) = P"
   "(P \<longrightarrow> True) = True"
   "(False \<longrightarrow> P) = True"
   "(P \<longrightarrow> P) = True"
   "(\<not> (A \<longleftrightarrow> \<not> B)) \<longleftrightarrow> (A \<longleftrightarrow> B)"
   by auto
 
 lemma [z3_rule]:
   "((P = Q) \<longrightarrow> R) = (R \<or> (Q = (\<not> P)))"
   by auto
 
 lemma [z3_rule]:
   "(\<not> True) = False"
   "(\<not> False) = True"
   "(x = x) = True"
   "(P = True) = P"
   "(True = P) = P"
   "(P = False) = (\<not> P)"
   "(False = P) = (\<not> P)"
   "((\<not> P) = P) = False"
   "(P = (\<not> P)) = False"
   "((\<not> P) = (\<not> Q)) = (P = Q)"
   "\<not> (P = (\<not> Q)) = (P = Q)"
   "\<not> ((\<not> P) = Q) = (P = Q)"
   "(P \<noteq> Q) = (Q = (\<not> P))"
   "(P = Q) = ((\<not> P \<or> Q) \<and> (P \<or> \<not> Q))"
   "(P \<noteq> Q) = ((\<not> P \<or> \<not> Q) \<and> (P \<or> Q))"
   by auto
 
 lemma [z3_rule]:
   "(if P then P else \<not> P) = True"
   "(if \<not> P then \<not> P else P) = True"
   "(if P then True else False) = P"
   "(if P then False else True) = (\<not> P)"
   "(if P then Q else True) = ((\<not> P) \<or> Q)"
   "(if P then Q else True) = (Q \<or> (\<not> P))"
   "(if P then Q else \<not> Q) = (P = Q)"
   "(if P then Q else \<not> Q) = (Q = P)"
   "(if P then \<not> Q else Q) = (P = (\<not> Q))"
   "(if P then \<not> Q else Q) = ((\<not> Q) = P)"
   "(if \<not> P then x else y) = (if P then y else x)"
   "(if P then (if Q then x else y) else x) = (if P \<and> (\<not> Q) then y else x)"
   "(if P then (if Q then x else y) else x) = (if (\<not> Q) \<and> P then y else x)"
   "(if P then (if Q then x else y) else y) = (if P \<and> Q then x else y)"
   "(if P then (if Q then x else y) else y) = (if Q \<and> P then x else y)"
   "(if P then x else if P then y else z) = (if P then x else z)"
   "(if P then x else if Q then x else y) = (if P \<or> Q then x else y)"
   "(if P then x else if Q then x else y) = (if Q \<or> P then x else y)"
   "(if P then x = y else x = z) = (x = (if P then y else z))"
   "(if P then x = y else y = z) = (y = (if P then x else z))"
   "(if P then x = y else z = y) = (y = (if P then x else z))"
   by auto
 
 lemma [z3_rule]:
   "0 + (x::int) = x"
   "x + 0 = x"
   "x + x = 2 * x"
   "0 * x = 0"
   "1 * x = x"
   "x + y = y + x"
   by auto
 
 lemma [z3_rule]:  (* for def-axiom *)
   "P = Q \<or> P \<or> Q"
   "P = Q \<or> \<not> P \<or> \<not> Q"
   "(\<not> P) = Q \<or> \<not> P \<or> Q"
   "(\<not> P) = Q \<or> P \<or> \<not> Q"
   "P = (\<not> Q) \<or> \<not> P \<or> Q"
   "P = (\<not> Q) \<or> P \<or> \<not> Q"
   "P \<noteq> Q \<or> P \<or> \<not> Q"
   "P \<noteq> Q \<or> \<not> P \<or> Q"
   "P \<noteq> (\<not> Q) \<or> P \<or> Q"
   "(\<not> P) \<noteq> Q \<or> P \<or> Q"
   "P \<or> Q \<or> P \<noteq> (\<not> Q)"
   "P \<or> Q \<or> (\<not> P) \<noteq> Q"
   "P \<or> \<not> Q \<or> P \<noteq> Q"
   "\<not> P \<or> Q \<or> P \<noteq> Q"
   "P \<or> y = (if P then x else y)"
   "P \<or> (if P then x else y) = y"
   "\<not> P \<or> x = (if P then x else y)"
   "\<not> P \<or> (if P then x else y) = x"
   "P \<or> R \<or> \<not> (if P then Q else R)"
   "\<not> P \<or> Q \<or> \<not> (if P then Q else R)"
   "\<not> (if P then Q else R) \<or> \<not> P \<or> Q"
   "\<not> (if P then Q else R) \<or> P \<or> R"
   "(if P then Q else R) \<or> \<not> P \<or> \<not> Q"
   "(if P then Q else R) \<or> P \<or> \<not> R"
   "(if P then \<not> Q else R) \<or> \<not> P \<or> Q"
   "(if P then Q else \<not> R) \<or> P \<or> R"
   by auto
 
 hide_type (open) symb_list pattern
 hide_const (open) Symb_Nil Symb_Cons trigger pat nopat fun_app z3div z3mod
 
 end