diff --git a/src/HOL/Lattices_Big.thy b/src/HOL/Lattices_Big.thy
--- a/src/HOL/Lattices_Big.thy
+++ b/src/HOL/Lattices_Big.thy
@@ -1,845 +1,874 @@
 (*  Title:      HOL/Lattices_Big.thy
     Author:     Tobias Nipkow, Lawrence C Paulson and Markus Wenzel
                 with contributions by Jeremy Avigad
 *)
 
 section \<open>Big infimum (minimum) and supremum (maximum) over finite (non-empty) sets\<close>
 
 theory Lattices_Big
 imports Finite_Set Option
 begin
 
 subsection \<open>Generic lattice operations over a set\<close>
 
 subsubsection \<open>Without neutral element\<close>
 
 locale semilattice_set = semilattice
 begin
 
 interpretation comp_fun_idem f
   by standard (simp_all add: fun_eq_iff left_commute)
 
 definition F :: "'a set \<Rightarrow> 'a"
 where
   eq_fold': "F A = the (Finite_Set.fold (\<lambda>x y. Some (case y of None \<Rightarrow> x | Some z \<Rightarrow> f x z)) None A)"
 
 lemma eq_fold:
   assumes "finite A"
   shows "F (insert x A) = Finite_Set.fold f x A"
 proof (rule sym)
   let ?f = "\<lambda>x y. Some (case y of None \<Rightarrow> x | Some z \<Rightarrow> f x z)"
   interpret comp_fun_idem "?f"
     by standard (simp_all add: fun_eq_iff commute left_commute split: option.split)
   from assms show "Finite_Set.fold f x A = F (insert x A)"
   proof induct
     case empty then show ?case by (simp add: eq_fold')
   next
     case (insert y B) then show ?case by (simp add: insert_commute [of x] eq_fold')
   qed
 qed
 
 lemma singleton [simp]:
   "F {x} = x"
   by (simp add: eq_fold)
 
 lemma insert_not_elem:
   assumes "finite A" and "x \<notin> A" and "A \<noteq> {}"
   shows "F (insert x A) = x \<^bold>* F A"
 proof -
   from \<open>A \<noteq> {}\<close> obtain b where "b \<in> A" by blast
   then obtain B where *: "A = insert b B" "b \<notin> B" by (blast dest: mk_disjoint_insert)
   with \<open>finite A\<close> and \<open>x \<notin> A\<close>
     have "finite (insert x B)" and "b \<notin> insert x B" by auto
   then have "F (insert b (insert x B)) = x \<^bold>* F (insert b B)"
     by (simp add: eq_fold)
   then show ?thesis by (simp add: * insert_commute)
 qed
 
 lemma in_idem:
   assumes "finite A" and "x \<in> A"
   shows "x \<^bold>* F A = F A"
 proof -
   from assms have "A \<noteq> {}" by auto
   with \<open>finite A\<close> show ?thesis using \<open>x \<in> A\<close>
     by (induct A rule: finite_ne_induct) (auto simp add: ac_simps insert_not_elem)
 qed
 
 lemma insert [simp]:
   assumes "finite A" and "A \<noteq> {}"
   shows "F (insert x A) = x \<^bold>* F A"
   using assms by (cases "x \<in> A") (simp_all add: insert_absorb in_idem insert_not_elem)
 
 lemma union:
   assumes "finite A" "A \<noteq> {}" and "finite B" "B \<noteq> {}"
   shows "F (A \<union> B) = F A \<^bold>* F B"
   using assms by (induct A rule: finite_ne_induct) (simp_all add: ac_simps)
 
 lemma remove:
   assumes "finite A" and "x \<in> A"
   shows "F A = (if A - {x} = {} then x else x \<^bold>* F (A - {x}))"
 proof -
   from assms obtain B where "A = insert x B" and "x \<notin> B" by (blast dest: mk_disjoint_insert)
   with assms show ?thesis by simp
 qed
 
 lemma insert_remove:
   assumes "finite A"
   shows "F (insert x A) = (if A - {x} = {} then x else x \<^bold>* F (A - {x}))"
   using assms by (cases "x \<in> A") (simp_all add: insert_absorb remove)
 
 lemma subset:
   assumes "finite A" "B \<noteq> {}" and "B \<subseteq> A"
   shows "F B \<^bold>* F A = F A"
 proof -
   from assms have "A \<noteq> {}" and "finite B" by (auto dest: finite_subset)
   with assms show ?thesis by (simp add: union [symmetric] Un_absorb1)
 qed
 
 lemma closed:
   assumes "finite A" "A \<noteq> {}" and elem: "\<And>x y. x \<^bold>* y \<in> {x, y}"
   shows "F A \<in> A"
 using \<open>finite A\<close> \<open>A \<noteq> {}\<close> proof (induct rule: finite_ne_induct)
   case singleton then show ?case by simp
 next
   case insert with elem show ?case by force
 qed
 
 lemma hom_commute:
   assumes hom: "\<And>x y. h (x \<^bold>* y) = h x \<^bold>* h y"
   and N: "finite N" "N \<noteq> {}"
   shows "h (F N) = F (h ` N)"
 using N proof (induct rule: finite_ne_induct)
   case singleton thus ?case by simp
 next
   case (insert n N)
   then have "h (F (insert n N)) = h (n \<^bold>* F N)" by simp
   also have "\<dots> = h n \<^bold>* h (F N)" by (rule hom)
   also have "h (F N) = F (h ` N)" by (rule insert)
   also have "h n \<^bold>* \<dots> = F (insert (h n) (h ` N))"
     using insert by simp
   also have "insert (h n) (h ` N) = h ` insert n N" by simp
   finally show ?case .
 qed
 
 lemma infinite: "\<not> finite A \<Longrightarrow> F A = the None"
   unfolding eq_fold' by (cases "finite (UNIV::'a set)") (auto intro: finite_subset fold_infinite)
 
 end
 
 locale semilattice_order_set = binary?: semilattice_order + semilattice_set
 begin
 
 lemma bounded_iff:
   assumes "finite A" and "A \<noteq> {}"
   shows "x \<^bold>\<le> F A \<longleftrightarrow> (\<forall>a\<in>A. x \<^bold>\<le> a)"
   using assms by (induct rule: finite_ne_induct) (simp_all add: bounded_iff)
 
 lemma boundedI:
   assumes "finite A"
   assumes "A \<noteq> {}"
   assumes "\<And>a. a \<in> A \<Longrightarrow> x \<^bold>\<le> a"
   shows "x \<^bold>\<le> F A"
   using assms by (simp add: bounded_iff)
 
 lemma boundedE:
   assumes "finite A" and "A \<noteq> {}" and "x \<^bold>\<le> F A"
   obtains "\<And>a. a \<in> A \<Longrightarrow> x \<^bold>\<le> a"
   using assms by (simp add: bounded_iff)
 
 lemma coboundedI:
   assumes "finite A"
     and "a \<in> A"
   shows "F A \<^bold>\<le> a"
 proof -
   from assms have "A \<noteq> {}" by auto
   from \<open>finite A\<close> \<open>A \<noteq> {}\<close> \<open>a \<in> A\<close> show ?thesis
   proof (induct rule: finite_ne_induct)
     case singleton thus ?case by (simp add: refl)
   next
     case (insert x B)
     from insert have "a = x \<or> a \<in> B" by simp
     then show ?case using insert by (auto intro: coboundedI2)
   qed
 qed
 
 lemma antimono:
   assumes "A \<subseteq> B" and "A \<noteq> {}" and "finite B"
   shows "F B \<^bold>\<le> F A"
 proof (cases "A = B")
   case True then show ?thesis by (simp add: refl)
 next
   case False
   have B: "B = A \<union> (B - A)" using \<open>A \<subseteq> B\<close> by blast
   then have "F B = F (A \<union> (B - A))" by simp
   also have "\<dots> = F A \<^bold>* F (B - A)" using False assms by (subst union) (auto intro: finite_subset)
   also have "\<dots> \<^bold>\<le> F A" by simp
   finally show ?thesis .
 qed
 
 end
 
 
 subsubsection \<open>With neutral element\<close>
 
 locale semilattice_neutr_set = semilattice_neutr
 begin
 
 interpretation comp_fun_idem f
   by standard (simp_all add: fun_eq_iff left_commute)
 
 definition F :: "'a set \<Rightarrow> 'a"
 where
   eq_fold: "F A = Finite_Set.fold f \<^bold>1 A"
 
 lemma infinite [simp]:
   "\<not> finite A \<Longrightarrow> F A = \<^bold>1"
   by (simp add: eq_fold)
 
 lemma empty [simp]:
   "F {} = \<^bold>1"
   by (simp add: eq_fold)
 
 lemma insert [simp]:
   assumes "finite A"
   shows "F (insert x A) = x \<^bold>* F A"
   using assms by (simp add: eq_fold)
 
 lemma in_idem:
   assumes "finite A" and "x \<in> A"
   shows "x \<^bold>* F A = F A"
 proof -
   from assms have "A \<noteq> {}" by auto
   with \<open>finite A\<close> show ?thesis using \<open>x \<in> A\<close>
     by (induct A rule: finite_ne_induct) (auto simp add: ac_simps)
 qed
 
 lemma union:
   assumes "finite A" and "finite B"
   shows "F (A \<union> B) = F A \<^bold>* F B"
   using assms by (induct A) (simp_all add: ac_simps)
 
 lemma remove:
   assumes "finite A" and "x \<in> A"
   shows "F A = x \<^bold>* F (A - {x})"
 proof -
   from assms obtain B where "A = insert x B" and "x \<notin> B" by (blast dest: mk_disjoint_insert)
   with assms show ?thesis by simp
 qed
 
 lemma insert_remove:
   assumes "finite A"
   shows "F (insert x A) = x \<^bold>* F (A - {x})"
   using assms by (cases "x \<in> A") (simp_all add: insert_absorb remove)
 
 lemma subset:
   assumes "finite A" and "B \<subseteq> A"
   shows "F B \<^bold>* F A = F A"
 proof -
   from assms have "finite B" by (auto dest: finite_subset)
   with assms show ?thesis by (simp add: union [symmetric] Un_absorb1)
 qed
 
 lemma closed:
   assumes "finite A" "A \<noteq> {}" and elem: "\<And>x y. x \<^bold>* y \<in> {x, y}"
   shows "F A \<in> A"
 using \<open>finite A\<close> \<open>A \<noteq> {}\<close> proof (induct rule: finite_ne_induct)
   case singleton then show ?case by simp
 next
   case insert with elem show ?case by force
 qed
 
 end
 
 locale semilattice_order_neutr_set = binary?: semilattice_neutr_order + semilattice_neutr_set
 begin
 
 lemma bounded_iff:
   assumes "finite A"
   shows "x \<^bold>\<le> F A \<longleftrightarrow> (\<forall>a\<in>A. x \<^bold>\<le> a)"
   using assms by (induct A) (simp_all add: bounded_iff)
 
 lemma boundedI:
   assumes "finite A"
   assumes "\<And>a. a \<in> A \<Longrightarrow> x \<^bold>\<le> a"
   shows "x \<^bold>\<le> F A"
   using assms by (simp add: bounded_iff)
 
 lemma boundedE:
   assumes "finite A" and "x \<^bold>\<le> F A"
   obtains "\<And>a. a \<in> A \<Longrightarrow> x \<^bold>\<le> a"
   using assms by (simp add: bounded_iff)
 
 lemma coboundedI:
   assumes "finite A"
     and "a \<in> A"
   shows "F A \<^bold>\<le> a"
 proof -
   from assms have "A \<noteq> {}" by auto
   from \<open>finite A\<close> \<open>A \<noteq> {}\<close> \<open>a \<in> A\<close> show ?thesis
   proof (induct rule: finite_ne_induct)
     case singleton thus ?case by (simp add: refl)
   next
     case (insert x B)
     from insert have "a = x \<or> a \<in> B" by simp
     then show ?case using insert by (auto intro: coboundedI2)
   qed
 qed
 
 lemma antimono:
   assumes "A \<subseteq> B" and "finite B"
   shows "F B \<^bold>\<le> F A"
 proof (cases "A = B")
   case True then show ?thesis by (simp add: refl)
 next
   case False
   have B: "B = A \<union> (B - A)" using \<open>A \<subseteq> B\<close> by blast
   then have "F B = F (A \<union> (B - A))" by simp
   also have "\<dots> = F A \<^bold>* F (B - A)" using False assms by (subst union) (auto intro: finite_subset)
   also have "\<dots> \<^bold>\<le> F A" by simp
   finally show ?thesis .
 qed
 
 end
 
 
 subsection \<open>Lattice operations on finite sets\<close>
 
 context semilattice_inf
 begin
 
 sublocale Inf_fin: semilattice_order_set inf less_eq less
 defines
   Inf_fin ("\<Sqinter>\<^sub>f\<^sub>i\<^sub>n_" [900] 900) = Inf_fin.F ..
 
 end
 
 context semilattice_sup
 begin
 
 sublocale Sup_fin: semilattice_order_set sup greater_eq greater
 defines
   Sup_fin ("\<Squnion>\<^sub>f\<^sub>i\<^sub>n_" [900] 900) = Sup_fin.F ..
 
 end
 
 
 subsection \<open>Infimum and Supremum over non-empty sets\<close>
 
 context lattice
 begin
 
 lemma Inf_fin_le_Sup_fin [simp]: 
   assumes "finite A" and "A \<noteq> {}"
   shows "\<Sqinter>\<^sub>f\<^sub>i\<^sub>nA \<le> \<Squnion>\<^sub>f\<^sub>i\<^sub>nA"
 proof -
   from \<open>A \<noteq> {}\<close> obtain a where "a \<in> A" by blast
   with \<open>finite A\<close> have "\<Sqinter>\<^sub>f\<^sub>i\<^sub>nA \<le> a" by (rule Inf_fin.coboundedI)
   moreover from \<open>finite A\<close> \<open>a \<in> A\<close> have "a \<le> \<Squnion>\<^sub>f\<^sub>i\<^sub>nA" by (rule Sup_fin.coboundedI)
   ultimately show ?thesis by (rule order_trans)
 qed
 
 lemma sup_Inf_absorb [simp]:
   "finite A \<Longrightarrow> a \<in> A \<Longrightarrow> \<Sqinter>\<^sub>f\<^sub>i\<^sub>nA \<squnion> a = a"
   by (rule sup_absorb2) (rule Inf_fin.coboundedI)
 
 lemma inf_Sup_absorb [simp]:
   "finite A \<Longrightarrow> a \<in> A \<Longrightarrow> a \<sqinter> \<Squnion>\<^sub>f\<^sub>i\<^sub>nA = a"
   by (rule inf_absorb1) (rule Sup_fin.coboundedI)
 
 end
 
 context distrib_lattice
 begin
 
 lemma sup_Inf1_distrib:
   assumes "finite A"
     and "A \<noteq> {}"
   shows "sup x (\<Sqinter>\<^sub>f\<^sub>i\<^sub>nA) = \<Sqinter>\<^sub>f\<^sub>i\<^sub>n{sup x a|a. a \<in> A}"
 using assms by (simp add: image_def Inf_fin.hom_commute [where h="sup x", OF sup_inf_distrib1])
   (rule arg_cong [where f="Inf_fin"], blast)
 
 lemma sup_Inf2_distrib:
   assumes A: "finite A" "A \<noteq> {}" and B: "finite B" "B \<noteq> {}"
   shows "sup (\<Sqinter>\<^sub>f\<^sub>i\<^sub>nA) (\<Sqinter>\<^sub>f\<^sub>i\<^sub>nB) = \<Sqinter>\<^sub>f\<^sub>i\<^sub>n{sup a b|a b. a \<in> A \<and> b \<in> B}"
 using A proof (induct rule: finite_ne_induct)
   case singleton then show ?case
     by (simp add: sup_Inf1_distrib [OF B])
 next
   case (insert x A)
   have finB: "finite {sup x b |b. b \<in> B}"
     by (rule finite_surj [where f = "sup x", OF B(1)], auto)
   have finAB: "finite {sup a b |a b. a \<in> A \<and> b \<in> B}"
   proof -
     have "{sup a b |a b. a \<in> A \<and> b \<in> B} = (UN a:A. UN b:B. {sup a b})"
       by blast
     thus ?thesis by(simp add: insert(1) B(1))
   qed
   have ne: "{sup a b |a b. a \<in> A \<and> b \<in> B} \<noteq> {}" using insert B by blast
   have "sup (\<Sqinter>\<^sub>f\<^sub>i\<^sub>n(insert x A)) (\<Sqinter>\<^sub>f\<^sub>i\<^sub>nB) = sup (inf x (\<Sqinter>\<^sub>f\<^sub>i\<^sub>nA)) (\<Sqinter>\<^sub>f\<^sub>i\<^sub>nB)"
     using insert by simp
   also have "\<dots> = inf (sup x (\<Sqinter>\<^sub>f\<^sub>i\<^sub>nB)) (sup (\<Sqinter>\<^sub>f\<^sub>i\<^sub>nA) (\<Sqinter>\<^sub>f\<^sub>i\<^sub>nB))" by(rule sup_inf_distrib2)
   also have "\<dots> = inf (\<Sqinter>\<^sub>f\<^sub>i\<^sub>n{sup x b|b. b \<in> B}) (\<Sqinter>\<^sub>f\<^sub>i\<^sub>n{sup a b|a b. a \<in> A \<and> b \<in> B})"
     using insert by(simp add:sup_Inf1_distrib[OF B])
   also have "\<dots> = \<Sqinter>\<^sub>f\<^sub>i\<^sub>n({sup x b |b. b \<in> B} \<union> {sup a b |a b. a \<in> A \<and> b \<in> B})"
     (is "_ = \<Sqinter>\<^sub>f\<^sub>i\<^sub>n?M")
     using B insert
     by (simp add: Inf_fin.union [OF finB _ finAB ne])
   also have "?M = {sup a b |a b. a \<in> insert x A \<and> b \<in> B}"
     by blast
   finally show ?case .
 qed
 
 lemma inf_Sup1_distrib:
   assumes "finite A" and "A \<noteq> {}"
   shows "inf x (\<Squnion>\<^sub>f\<^sub>i\<^sub>nA) = \<Squnion>\<^sub>f\<^sub>i\<^sub>n{inf x a|a. a \<in> A}"
 using assms by (simp add: image_def Sup_fin.hom_commute [where h="inf x", OF inf_sup_distrib1])
   (rule arg_cong [where f="Sup_fin"], blast)
 
 lemma inf_Sup2_distrib:
   assumes A: "finite A" "A \<noteq> {}" and B: "finite B" "B \<noteq> {}"
   shows "inf (\<Squnion>\<^sub>f\<^sub>i\<^sub>nA) (\<Squnion>\<^sub>f\<^sub>i\<^sub>nB) = \<Squnion>\<^sub>f\<^sub>i\<^sub>n{inf a b|a b. a \<in> A \<and> b \<in> B}"
 using A proof (induct rule: finite_ne_induct)
   case singleton thus ?case
     by(simp add: inf_Sup1_distrib [OF B])
 next
   case (insert x A)
   have finB: "finite {inf x b |b. b \<in> B}"
     by(rule finite_surj[where f = "%b. inf x b", OF B(1)], auto)
   have finAB: "finite {inf a b |a b. a \<in> A \<and> b \<in> B}"
   proof -
     have "{inf a b |a b. a \<in> A \<and> b \<in> B} = (UN a:A. UN b:B. {inf a b})"
       by blast
     thus ?thesis by(simp add: insert(1) B(1))
   qed
   have ne: "{inf a b |a b. a \<in> A \<and> b \<in> B} \<noteq> {}" using insert B by blast
   have "inf (\<Squnion>\<^sub>f\<^sub>i\<^sub>n(insert x A)) (\<Squnion>\<^sub>f\<^sub>i\<^sub>nB) = inf (sup x (\<Squnion>\<^sub>f\<^sub>i\<^sub>nA)) (\<Squnion>\<^sub>f\<^sub>i\<^sub>nB)"
     using insert by simp
   also have "\<dots> = sup (inf x (\<Squnion>\<^sub>f\<^sub>i\<^sub>nB)) (inf (\<Squnion>\<^sub>f\<^sub>i\<^sub>nA) (\<Squnion>\<^sub>f\<^sub>i\<^sub>nB))" by(rule inf_sup_distrib2)
   also have "\<dots> = sup (\<Squnion>\<^sub>f\<^sub>i\<^sub>n{inf x b|b. b \<in> B}) (\<Squnion>\<^sub>f\<^sub>i\<^sub>n{inf a b|a b. a \<in> A \<and> b \<in> B})"
     using insert by(simp add:inf_Sup1_distrib[OF B])
   also have "\<dots> = \<Squnion>\<^sub>f\<^sub>i\<^sub>n({inf x b |b. b \<in> B} \<union> {inf a b |a b. a \<in> A \<and> b \<in> B})"
     (is "_ = \<Squnion>\<^sub>f\<^sub>i\<^sub>n?M")
     using B insert
     by (simp add: Sup_fin.union [OF finB _ finAB ne])
   also have "?M = {inf a b |a b. a \<in> insert x A \<and> b \<in> B}"
     by blast
   finally show ?case .
 qed
 
 end
 
 context complete_lattice
 begin
 
 lemma Inf_fin_Inf:
   assumes "finite A" and "A \<noteq> {}"
   shows "\<Sqinter>\<^sub>f\<^sub>i\<^sub>nA = \<Sqinter>A"
 proof -
   from assms obtain b B where "A = insert b B" and "finite B" by auto
   then show ?thesis
     by (simp add: Inf_fin.eq_fold inf_Inf_fold_inf inf.commute [of b])
 qed
 
 lemma Sup_fin_Sup:
   assumes "finite A" and "A \<noteq> {}"
   shows "\<Squnion>\<^sub>f\<^sub>i\<^sub>nA = \<Squnion>A"
 proof -
   from assms obtain b B where "A = insert b B" and "finite B" by auto
   then show ?thesis
     by (simp add: Sup_fin.eq_fold sup_Sup_fold_sup sup.commute [of b])
 qed
 
 end
 
 
 subsection \<open>Minimum and Maximum over non-empty sets\<close>
 
 context linorder
 begin
 
 sublocale Min: semilattice_order_set min less_eq less
   + Max: semilattice_order_set max greater_eq greater
 defines
   Min = Min.F and Max = Max.F ..
 
 end
 
 text \<open>An aside: @{const Min}/@{const Max} on linear orders as special case of @{const Inf_fin}/@{const Sup_fin}\<close>
 
 lemma Inf_fin_Min:
   "Inf_fin = (Min :: 'a::{semilattice_inf, linorder} set \<Rightarrow> 'a)"
   by (simp add: Inf_fin_def Min_def inf_min)
 
 lemma Sup_fin_Max:
   "Sup_fin = (Max :: 'a::{semilattice_sup, linorder} set \<Rightarrow> 'a)"
   by (simp add: Sup_fin_def Max_def sup_max)
 
 context linorder
 begin
 
 lemma dual_min:
   "ord.min greater_eq = max"
   by (auto simp add: ord.min_def max_def fun_eq_iff)
 
 lemma dual_max:
   "ord.max greater_eq = min"
   by (auto simp add: ord.max_def min_def fun_eq_iff)
 
 lemma dual_Min:
   "linorder.Min greater_eq = Max"
 proof -
   interpret dual: linorder greater_eq greater by (fact dual_linorder)
   show ?thesis by (simp add: dual.Min_def dual_min Max_def)
 qed
 
 lemma dual_Max:
   "linorder.Max greater_eq = Min"
 proof -
   interpret dual: linorder greater_eq greater by (fact dual_linorder)
   show ?thesis by (simp add: dual.Max_def dual_max Min_def)
 qed
 
 lemmas Min_singleton = Min.singleton
 lemmas Max_singleton = Max.singleton
 lemmas Min_insert = Min.insert
 lemmas Max_insert = Max.insert
 lemmas Min_Un = Min.union
 lemmas Max_Un = Max.union
 lemmas hom_Min_commute = Min.hom_commute
 lemmas hom_Max_commute = Max.hom_commute
 
 lemma Min_in [simp]:
   assumes "finite A" and "A \<noteq> {}"
   shows "Min A \<in> A"
   using assms by (auto simp add: min_def Min.closed)
 
 lemma Max_in [simp]:
   assumes "finite A" and "A \<noteq> {}"
   shows "Max A \<in> A"
   using assms by (auto simp add: max_def Max.closed)
 
 lemma Min_insert2:
   assumes "finite A" and min: "\<And>b. b \<in> A \<Longrightarrow> a \<le> b"
   shows "Min (insert a A) = a"
 proof (cases "A = {}")
   case True
   then show ?thesis by simp
 next
   case False
   with \<open>finite A\<close> have "Min (insert a A) = min a (Min A)"
     by simp
   moreover from \<open>finite A\<close> \<open>A \<noteq> {}\<close> min have "a \<le> Min A" by simp
   ultimately show ?thesis by (simp add: min.absorb1)
 qed
 
 lemma Max_insert2:
   assumes "finite A" and max: "\<And>b. b \<in> A \<Longrightarrow> b \<le> a"
   shows "Max (insert a A) = a"
 proof (cases "A = {}")
   case True
   then show ?thesis by simp
 next
   case False
   with \<open>finite A\<close> have "Max (insert a A) = max a (Max A)"
     by simp
   moreover from \<open>finite A\<close> \<open>A \<noteq> {}\<close> max have "Max A \<le> a" by simp
   ultimately show ?thesis by (simp add: max.absorb1)
 qed
 
 lemma Min_le [simp]:
   assumes "finite A" and "x \<in> A"
   shows "Min A \<le> x"
   using assms by (fact Min.coboundedI)
 
 lemma Max_ge [simp]:
   assumes "finite A" and "x \<in> A"
   shows "x \<le> Max A"
   using assms by (fact Max.coboundedI)
 
 lemma Min_eqI:
   assumes "finite A"
   assumes "\<And>y. y \<in> A \<Longrightarrow> y \<ge> x"
     and "x \<in> A"
   shows "Min A = x"
 proof (rule antisym)
   from \<open>x \<in> A\<close> have "A \<noteq> {}" by auto
   with assms show "Min A \<ge> x" by simp
 next
   from assms show "x \<ge> Min A" by simp
 qed
 
 lemma Max_eqI:
   assumes "finite A"
   assumes "\<And>y. y \<in> A \<Longrightarrow> y \<le> x"
     and "x \<in> A"
   shows "Max A = x"
 proof (rule antisym)
   from \<open>x \<in> A\<close> have "A \<noteq> {}" by auto
   with assms show "Max A \<le> x" by simp
 next
   from assms show "x \<le> Max A" by simp
 qed
 
 context
   fixes A :: "'a set"
   assumes fin_nonempty: "finite A" "A \<noteq> {}"
 begin
 
 lemma Min_ge_iff [simp]:
   "x \<le> Min A \<longleftrightarrow> (\<forall>a\<in>A. x \<le> a)"
   using fin_nonempty by (fact Min.bounded_iff)
 
 lemma Max_le_iff [simp]:
   "Max A \<le> x \<longleftrightarrow> (\<forall>a\<in>A. a \<le> x)"
   using fin_nonempty by (fact Max.bounded_iff)
 
 lemma Min_gr_iff [simp]:
   "x < Min A \<longleftrightarrow> (\<forall>a\<in>A. x < a)"
   using fin_nonempty  by (induct rule: finite_ne_induct) simp_all
 
 lemma Max_less_iff [simp]:
   "Max A < x \<longleftrightarrow> (\<forall>a\<in>A. a < x)"
   using fin_nonempty by (induct rule: finite_ne_induct) simp_all
 
 lemma Min_le_iff:
   "Min A \<le> x \<longleftrightarrow> (\<exists>a\<in>A. a \<le> x)"
   using fin_nonempty by (induct rule: finite_ne_induct) (simp_all add: min_le_iff_disj)
 
 lemma Max_ge_iff:
   "x \<le> Max A \<longleftrightarrow> (\<exists>a\<in>A. x \<le> a)"
   using fin_nonempty by (induct rule: finite_ne_induct) (simp_all add: le_max_iff_disj)
 
 lemma Min_less_iff:
   "Min A < x \<longleftrightarrow> (\<exists>a\<in>A. a < x)"
   using fin_nonempty by (induct rule: finite_ne_induct) (simp_all add: min_less_iff_disj)
 
 lemma Max_gr_iff:
   "x < Max A \<longleftrightarrow> (\<exists>a\<in>A. x < a)"
   using fin_nonempty by (induct rule: finite_ne_induct) (simp_all add: less_max_iff_disj)
 
 end
 
 lemma Max_eq_if:
   assumes "finite A"  "finite B"  "\<forall>a\<in>A. \<exists>b\<in>B. a \<le> b"  "\<forall>b\<in>B. \<exists>a\<in>A. b \<le> a"
   shows "Max A = Max B"
 proof cases
   assume "A = {}" thus ?thesis using assms by simp
 next
   assume "A \<noteq> {}" thus ?thesis using assms
     by(blast intro: antisym Max_in Max_ge_iff[THEN iffD2])
 qed
 
 lemma Min_antimono:
   assumes "M \<subseteq> N" and "M \<noteq> {}" and "finite N"
   shows "Min N \<le> Min M"
   using assms by (fact Min.antimono)
 
 lemma Max_mono:
   assumes "M \<subseteq> N" and "M \<noteq> {}" and "finite N"
   shows "Max M \<le> Max N"
   using assms by (fact Max.antimono)
 
 end
 
 context linorder  (* FIXME *)
 begin
 
 lemma mono_Min_commute:
   assumes "mono f"
   assumes "finite A" and "A \<noteq> {}"
   shows "f (Min A) = Min (f ` A)"
 proof (rule linorder_class.Min_eqI [symmetric])
   from \<open>finite A\<close> show "finite (f ` A)" by simp
   from assms show "f (Min A) \<in> f ` A" by simp
   fix x
   assume "x \<in> f ` A"
   then obtain y where "y \<in> A" and "x = f y" ..
   with assms have "Min A \<le> y" by auto
   with \<open>mono f\<close> have "f (Min A) \<le> f y" by (rule monoE)
   with \<open>x = f y\<close> show "f (Min A) \<le> x" by simp
 qed
 
 lemma mono_Max_commute:
   assumes "mono f"
   assumes "finite A" and "A \<noteq> {}"
   shows "f (Max A) = Max (f ` A)"
 proof (rule linorder_class.Max_eqI [symmetric])
   from \<open>finite A\<close> show "finite (f ` A)" by simp
   from assms show "f (Max A) \<in> f ` A" by simp
   fix x
   assume "x \<in> f ` A"
   then obtain y where "y \<in> A" and "x = f y" ..
   with assms have "y \<le> Max A" by auto
   with \<open>mono f\<close> have "f y \<le> f (Max A)" by (rule monoE)
   with \<open>x = f y\<close> show "x \<le> f (Max A)" by simp
 qed
 
 lemma finite_linorder_max_induct [consumes 1, case_names empty insert]:
   assumes fin: "finite A"
   and empty: "P {}" 
   and insert: "\<And>b A. finite A \<Longrightarrow> \<forall>a\<in>A. a < b \<Longrightarrow> P A \<Longrightarrow> P (insert b A)"
   shows "P A"
 using fin empty insert
 proof (induct rule: finite_psubset_induct)
   case (psubset A)
   have IH: "\<And>B. \<lbrakk>B < A; P {}; (\<And>A b. \<lbrakk>finite A; \<forall>a\<in>A. a<b; P A\<rbrakk> \<Longrightarrow> P (insert b A))\<rbrakk> \<Longrightarrow> P B" by fact 
   have fin: "finite A" by fact 
   have empty: "P {}" by fact
   have step: "\<And>b A. \<lbrakk>finite A; \<forall>a\<in>A. a < b; P A\<rbrakk> \<Longrightarrow> P (insert b A)" by fact
   show "P A"
   proof (cases "A = {}")
     assume "A = {}" 
     then show "P A" using \<open>P {}\<close> by simp
   next
     let ?B = "A - {Max A}" 
     let ?A = "insert (Max A) ?B"
     have "finite ?B" using \<open>finite A\<close> by simp
     assume "A \<noteq> {}"
     with \<open>finite A\<close> have "Max A : A" by auto
     then have A: "?A = A" using insert_Diff_single insert_absorb by auto
     then have "P ?B" using \<open>P {}\<close> step IH [of ?B] by blast
     moreover 
     have "\<forall>a\<in>?B. a < Max A" using Max_ge [OF \<open>finite A\<close>] by fastforce
     ultimately show "P A" using A insert_Diff_single step [OF \<open>finite ?B\<close>] by fastforce
   qed
 qed
 
 lemma finite_linorder_min_induct [consumes 1, case_names empty insert]:
   "\<lbrakk>finite A; P {}; \<And>b A. \<lbrakk>finite A; \<forall>a\<in>A. b < a; P A\<rbrakk> \<Longrightarrow> P (insert b A)\<rbrakk> \<Longrightarrow> P A"
   by (rule linorder.finite_linorder_max_induct [OF dual_linorder])
 
 lemma Least_Min:
   assumes "finite {a. P a}" and "\<exists>a. P a"
   shows "(LEAST a. P a) = Min {a. P a}"
 proof -
   { fix A :: "'a set"
     assume A: "finite A" "A \<noteq> {}"
     have "(LEAST a. a \<in> A) = Min A"
     using A proof (induct A rule: finite_ne_induct)
       case singleton show ?case by (rule Least_equality) simp_all
     next
       case (insert a A)
       have "(LEAST b. b = a \<or> b \<in> A) = min a (LEAST a. a \<in> A)"
         by (auto intro!: Least_equality simp add: min_def not_le Min_le_iff insert.hyps dest!: less_imp_le)
       with insert show ?case by simp
     qed
   } from this [of "{a. P a}"] assms show ?thesis by simp
 qed
 
 lemma infinite_growing:
   assumes "X \<noteq> {}"
   assumes *: "\<And>x. x \<in> X \<Longrightarrow> \<exists>y\<in>X. y > x"
   shows "\<not> finite X"
 proof
   assume "finite X"
   with \<open>X \<noteq> {}\<close> have "Max X \<in> X" "\<forall>x\<in>X. x \<le> Max X"
     by auto
   with *[of "Max X"] show False
     by auto
 qed
 
 end
 
 context linordered_ab_semigroup_add
 begin
 
 lemma add_Min_commute:
   fixes k
   assumes "finite N" and "N \<noteq> {}"
   shows "k + Min N = Min {k + m | m. m \<in> N}"
 proof -
   have "\<And>x y. k + min x y = min (k + x) (k + y)"
     by (simp add: min_def not_le)
       (blast intro: antisym less_imp_le add_left_mono)
   with assms show ?thesis
     using hom_Min_commute [of "plus k" N]
     by simp (blast intro: arg_cong [where f = Min])
 qed
 
 lemma add_Max_commute:
   fixes k
   assumes "finite N" and "N \<noteq> {}"
   shows "k + Max N = Max {k + m | m. m \<in> N}"
 proof -
   have "\<And>x y. k + max x y = max (k + x) (k + y)"
     by (simp add: max_def not_le)
       (blast intro: antisym less_imp_le add_left_mono)
   with assms show ?thesis
     using hom_Max_commute [of "plus k" N]
     by simp (blast intro: arg_cong [where f = Max])
 qed
 
 end
 
 context linordered_ab_group_add
 begin
 
 lemma minus_Max_eq_Min [simp]:
   "finite S \<Longrightarrow> S \<noteq> {} \<Longrightarrow> - Max S = Min (uminus ` S)"
   by (induct S rule: finite_ne_induct) (simp_all add: minus_max_eq_min)
 
 lemma minus_Min_eq_Max [simp]:
   "finite S \<Longrightarrow> S \<noteq> {} \<Longrightarrow> - Min S = Max (uminus ` S)"
   by (induct S rule: finite_ne_induct) (simp_all add: minus_min_eq_max)
 
 end
 
 context complete_linorder
 begin
 
 lemma Min_Inf:
   assumes "finite A" and "A \<noteq> {}"
   shows "Min A = Inf A"
 proof -
   from assms obtain b B where "A = insert b B" and "finite B" by auto
   then show ?thesis
     by (simp add: Min.eq_fold complete_linorder_inf_min [symmetric] inf_Inf_fold_inf inf.commute [of b])
 qed
 
 lemma Max_Sup:
   assumes "finite A" and "A \<noteq> {}"
   shows "Max A = Sup A"
 proof -
   from assms obtain b B where "A = insert b B" and "finite B" by auto
   then show ?thesis
     by (simp add: Max.eq_fold complete_linorder_sup_max [symmetric] sup_Sup_fold_sup sup.commute [of b])
 qed
 
 end
 
 
 subsection \<open>Arg Min\<close>
 
-definition args_min :: "('a \<Rightarrow> 'b::ord) \<Rightarrow> 'a set \<Rightarrow> 'a set" where
-"args_min f S = {x \<in> S. \<not>(\<exists>y \<in> S. f y < f x)}"
+definition is_arg_min :: "('a \<Rightarrow> 'b::ord) \<Rightarrow> ('a \<Rightarrow> bool) \<Rightarrow> 'a \<Rightarrow> bool" where
+"is_arg_min f P x = (P x \<and> \<not>(\<exists>y. P y \<and> f y < f x))"
 
-definition arg_min :: "('a \<Rightarrow> 'b::ord) \<Rightarrow> 'a set \<Rightarrow> 'a" where
-"arg_min f S = (SOME x. x \<in> args_min f S)"
+definition arg_min :: "('a \<Rightarrow> 'b::ord) \<Rightarrow> ('a \<Rightarrow> bool) \<Rightarrow> 'a" where
+"arg_min f P = (SOME x. is_arg_min f P x)"
 
-lemma args_min_linorder: fixes f :: "'a \<Rightarrow> 'b :: linorder"
-shows "args_min f S = {x \<in> S. \<forall>y \<in> S. f x \<le> f y}"
-by(auto simp add: args_min_def)
+abbreviation arg_min_on :: "('a \<Rightarrow> 'b::ord) \<Rightarrow> 'a set \<Rightarrow> 'a" where
+"arg_min_on f S \<equiv> arg_min f (\<lambda>x. x \<in> S)"
+
+lemma is_arg_min_linorder: fixes f :: "'a \<Rightarrow> 'b :: linorder"
+shows "is_arg_min f P x = (P x \<and> (\<forall>y. P y \<longrightarrow> f x \<le> f y))"
+by(auto simp add: is_arg_min_def)
+
+lemma arg_min_nat_lemma: "P k \<Longrightarrow> P(arg_min m P) \<and> (\<forall>y. P y \<longrightarrow> m (arg_min m P) \<le> m y)"
+  for m :: "'a \<Rightarrow> nat"
+apply (simp add: arg_min_def is_arg_min_linorder)
+apply (rule someI_ex)
+apply (erule ex_has_least_nat)
+done
+
+lemmas arg_min_natI = arg_min_nat_lemma [THEN conjunct1]
+
+lemma arg_min_nat_le: "P x \<Longrightarrow> m (arg_min m P) \<le> m x"
+  for m :: "'a \<Rightarrow> nat"
+by (rule arg_min_nat_lemma [THEN conjunct2, THEN spec, THEN mp])
+
+lemma ex_min_if_finite:
+  "\<lbrakk> finite S; S \<noteq> {} \<rbrakk> \<Longrightarrow> \<exists>m\<in>S. \<not>(\<exists>x\<in>S. x < (m::'a::order))"
+by(induction rule: finite.induct) (auto intro: order.strict_trans)
+
+lemma ex_is_arg_min_if_finite: fixes f :: "'a \<Rightarrow> 'b :: order"
+shows "\<lbrakk> finite S; S \<noteq> {} \<rbrakk> \<Longrightarrow> \<exists>x. is_arg_min f (\<lambda>x. x : S) x"
+unfolding is_arg_min_def
+using ex_min_if_finite[of "f ` S"]
+by auto
 
 lemma arg_min_SOME_Min:
-  "finite S \<Longrightarrow> arg_min f S = (SOME y. y \<in> S \<and> f y = Min(f ` S))"
-unfolding arg_min_def args_min_linorder
+  "finite S \<Longrightarrow> arg_min_on f S = (SOME y. y \<in> S \<and> f y = Min(f ` S))"
+unfolding arg_min_def is_arg_min_linorder
 apply(rule arg_cong[where f = Eps])
 apply (auto simp: fun_eq_iff intro: Min_eqI[symmetric])
 done
 
-lemma arg_min_in: fixes f :: "'a \<Rightarrow> 'b :: linorder"
-shows "finite S \<Longrightarrow> S \<noteq> {} \<Longrightarrow> arg_min f S \<in> S"
-by(simp add: arg_min_SOME_Min inv_into_def2[symmetric] inv_into_into)
+lemma arg_min_if_finite: fixes f :: "'a \<Rightarrow> 'b :: order"
+assumes "finite S" "S \<noteq> {}"
+shows  "arg_min_on f S \<in> S" and "\<not>(\<exists>x\<in>S. f x < f (arg_min_on f S))"
+using ex_is_arg_min_if_finite[OF assms, of f]
+unfolding arg_min_def is_arg_min_def
+by(auto dest!: someI_ex)
 
 lemma arg_min_least: fixes f :: "'a \<Rightarrow> 'b :: linorder"
-shows "\<lbrakk> finite S;  S \<noteq> {};  y \<in> S \<rbrakk> \<Longrightarrow> f(arg_min f S) \<le> f y"
+shows "\<lbrakk> finite S;  S \<noteq> {};  y \<in> S \<rbrakk> \<Longrightarrow> f(arg_min_on f S) \<le> f y"
 by(simp add: arg_min_SOME_Min inv_into_def2[symmetric] f_inv_into_f)
 
 lemma arg_min_inj_eq: fixes f :: "'a \<Rightarrow> 'b :: order"
-shows "\<lbrakk> inj_on f S; a \<in> S; \<forall>y \<in> S. f a \<le> f y \<rbrakk> \<Longrightarrow> arg_min f S = a"
-apply(simp add: arg_min_def args_min_def)
+shows "\<lbrakk> inj_on f {x. P x}; P a; \<forall>y. P y \<longrightarrow> f a \<le> f y \<rbrakk> \<Longrightarrow> arg_min f P = a"
+apply(simp add: arg_min_def is_arg_min_def)
 apply(rule someI2[of _ a])
  apply (simp add: less_le_not_le)
-by (metis inj_on_eq_iff less_le)
+by (metis inj_on_eq_iff less_le mem_Collect_eq)
 
 end