diff --git a/src/HOL/Analysis/Finite_Cartesian_Product.thy b/src/HOL/Analysis/Finite_Cartesian_Product.thy --- a/src/HOL/Analysis/Finite_Cartesian_Product.thy +++ b/src/HOL/Analysis/Finite_Cartesian_Product.thy @@ -1,1284 +1,1264 @@ (* Title: HOL/Analysis/Finite_Cartesian_Product.thy Author: Amine Chaieb, University of Cambridge *) section \Definition of Finite Cartesian Product Type\ theory Finite_Cartesian_Product imports Euclidean_Space L2_Norm "HOL-Library.Numeral_Type" "HOL-Library.Countable_Set" "HOL-Library.FuncSet" begin subsection\<^marker>\tag unimportant\ \Finite Cartesian products, with indexing and lambdas\ typedef ('a, 'b) vec = "UNIV :: ('b::finite \ 'a) set" morphisms vec_nth vec_lambda .. declare vec_lambda_inject [simplified, simp] bundle vec_syntax begin notation vec_nth (infixl "$" 90) and vec_lambda (binder "\" 10) end bundle no_vec_syntax begin no_notation vec_nth (infixl "$" 90) and vec_lambda (binder "\" 10) end unbundle vec_syntax text \ Concrete syntax for \('a, 'b) vec\: \<^item> \'a^'b\ becomes \('a, 'b::finite) vec\ \<^item> \'a^'b::_\ becomes \('a, 'b) vec\ without extra sort-constraint \ syntax "_vec_type" :: "type \ type \ type" (infixl "^" 15) parse_translation \ let fun vec t u = Syntax.const \<^type_syntax>\vec\ $ t $ u; fun finite_vec_tr [t, u] = (case Term_Position.strip_positions u of v as Free (x, _) => if Lexicon.is_tid x then vec t (Syntax.const \<^syntax_const>\_ofsort\ $ v $ Syntax.const \<^class_syntax>\finite\) else vec t u | _ => vec t u) in [(\<^syntax_const>\_vec_type\, K finite_vec_tr)] end \ lemma vec_eq_iff: "(x = y) \ (\i. x$i = y$i)" by (simp add: vec_nth_inject [symmetric] fun_eq_iff) lemma vec_lambda_beta [simp]: "vec_lambda g $ i = g i" by (simp add: vec_lambda_inverse) lemma vec_lambda_unique: "(\i. f$i = g i) \ vec_lambda g = f" by (auto simp add: vec_eq_iff) lemma vec_lambda_eta [simp]: "(\ i. (g$i)) = g" by (simp add: vec_eq_iff) subsection \Cardinality of vectors\ instance vec :: (finite, finite) finite proof show "finite (UNIV :: ('a, 'b) vec set)" proof (subst bij_betw_finite) show "bij_betw vec_nth UNIV (Pi (UNIV :: 'b set) (\_. UNIV :: 'a set))" by (intro bij_betwI[of _ _ _ vec_lambda]) (auto simp: vec_eq_iff) have "finite (PiE (UNIV :: 'b set) (\_. UNIV :: 'a set))" by (intro finite_PiE) auto also have "(PiE (UNIV :: 'b set) (\_. UNIV :: 'a set)) = Pi UNIV (\_. UNIV)" by auto finally show "finite \" . qed qed lemma countable_PiE: "finite I \ (\i. i \ I \ countable (F i)) \ countable (Pi\<^sub>E I F)" by (induct I arbitrary: F rule: finite_induct) (auto simp: PiE_insert_eq) instance vec :: (countable, finite) countable proof have "countable (UNIV :: ('a, 'b) vec set)" proof (rule countableI_bij2) show "bij_betw vec_nth UNIV (Pi (UNIV :: 'b set) (\_. UNIV :: 'a set))" by (intro bij_betwI[of _ _ _ vec_lambda]) (auto simp: vec_eq_iff) have "countable (PiE (UNIV :: 'b set) (\_. UNIV :: 'a set))" by (intro countable_PiE) auto also have "(PiE (UNIV :: 'b set) (\_. UNIV :: 'a set)) = Pi UNIV (\_. UNIV)" by auto finally show "countable \" . qed thus "\t::('a, 'b) vec \ nat. inj t" by (auto elim!: countableE) qed lemma infinite_UNIV_vec: assumes "infinite (UNIV :: 'a set)" shows "infinite (UNIV :: ('a^'b) set)" proof (subst bij_betw_finite) show "bij_betw vec_nth UNIV (Pi (UNIV :: 'b set) (\_. UNIV :: 'a set))" by (intro bij_betwI[of _ _ _ vec_lambda]) (auto simp: vec_eq_iff) have "infinite (PiE (UNIV :: 'b set) (\_. UNIV :: 'a set))" (is "infinite ?A") proof assume "finite ?A" hence "finite ((\f. f undefined) ` ?A)" by (rule finite_imageI) also have "(\f. f undefined) ` ?A = UNIV" by auto finally show False using \infinite (UNIV :: 'a set)\ by contradiction qed also have "?A = Pi UNIV (\_. UNIV)" by auto finally show "infinite (Pi (UNIV :: 'b set) (\_. UNIV :: 'a set))" . qed proposition CARD_vec [simp]: "CARD('a^'b) = CARD('a) ^ CARD('b)" proof (cases "finite (UNIV :: 'a set)") case True show ?thesis proof (subst bij_betw_same_card) show "bij_betw vec_nth UNIV (Pi (UNIV :: 'b set) (\_. UNIV :: 'a set))" by (intro bij_betwI[of _ _ _ vec_lambda]) (auto simp: vec_eq_iff) have "CARD('a) ^ CARD('b) = card (PiE (UNIV :: 'b set) (\_. UNIV :: 'a set))" (is "_ = card ?A") by (subst card_PiE) (auto) also have "?A = Pi UNIV (\_. UNIV)" by auto finally show "card \ = CARD('a) ^ CARD('b)" .. qed qed (simp_all add: infinite_UNIV_vec) lemma countable_vector: fixes B:: "'n::finite \ 'a set" assumes "\i. countable (B i)" shows "countable {V. \i::'n::finite. V $ i \ B i}" proof - have "f \ ($) ` {V. \i. V $ i \ B i}" if "f \ Pi\<^sub>E UNIV B" for f proof - have "\W. (\i. W $ i \ B i) \ ($) W = f" by (metis that PiE_iff UNIV_I vec_lambda_inverse) then show "f \ ($) ` {v. \i. v $ i \ B i}" by blast qed then have "Pi\<^sub>E UNIV B = vec_nth ` {V. \i::'n. V $ i \ B i}" by blast then have "countable (vec_nth ` {V. \i. V $ i \ B i})" by (metis finite_class.finite_UNIV countable_PiE assms) then have "countable (vec_lambda ` vec_nth ` {V. \i. V $ i \ B i})" by auto then show ?thesis by (simp add: image_comp o_def vec_nth_inverse) qed subsection\<^marker>\tag unimportant\ \Group operations and class instances\ instantiation vec :: (zero, finite) zero begin definition "0 \ (\ i. 0)" instance .. end instantiation vec :: (plus, finite) plus begin definition "(+) \ (\ x y. (\ i. x$i + y$i))" instance .. end instantiation vec :: (minus, finite) minus begin definition "(-) \ (\ x y. (\ i. x$i - y$i))" instance .. end instantiation vec :: (uminus, finite) uminus begin definition "uminus \ (\ x. (\ i. - (x$i)))" instance .. end lemma zero_index [simp]: "0 $ i = 0" unfolding zero_vec_def by simp lemma vector_add_component [simp]: "(x + y)$i = x$i + y$i" unfolding plus_vec_def by simp lemma vector_minus_component [simp]: "(x - y)$i = x$i - y$i" unfolding minus_vec_def by simp lemma vector_uminus_component [simp]: "(- x)$i = - (x$i)" unfolding uminus_vec_def by simp instance vec :: (semigroup_add, finite) semigroup_add by standard (simp add: vec_eq_iff add.assoc) instance vec :: (ab_semigroup_add, finite) ab_semigroup_add by standard (simp add: vec_eq_iff add.commute) instance vec :: (monoid_add, finite) monoid_add by standard (simp_all add: vec_eq_iff) instance vec :: (comm_monoid_add, finite) comm_monoid_add by standard (simp add: vec_eq_iff) instance vec :: (cancel_semigroup_add, finite) cancel_semigroup_add by standard (simp_all add: vec_eq_iff) instance vec :: (cancel_ab_semigroup_add, finite) cancel_ab_semigroup_add by standard (simp_all add: vec_eq_iff diff_diff_eq) instance vec :: (cancel_comm_monoid_add, finite) cancel_comm_monoid_add .. instance vec :: (group_add, finite) group_add by standard (simp_all add: vec_eq_iff) instance vec :: (ab_group_add, finite) ab_group_add by standard (simp_all add: vec_eq_iff) subsection\<^marker>\tag unimportant\\Basic componentwise operations on vectors\ instantiation vec :: (times, finite) times begin definition "(*) \ (\ x y. (\ i. (x$i) * (y$i)))" instance .. end instantiation vec :: (one, finite) one begin definition "1 \ (\ i. 1)" instance .. end instantiation vec :: (ord, finite) ord begin definition "x \ y \ (\i. x$i \ y$i)" definition "x < (y::'a^'b) \ x \ y \ \ y \ x" instance .. end text\The ordering on one-dimensional vectors is linear.\ instance vec:: (order, finite) order by standard (auto simp: less_eq_vec_def less_vec_def vec_eq_iff intro: order.trans order.antisym order.strict_implies_order) instance vec :: (linorder, CARD_1) linorder proof obtain a :: 'b where all: "\P. (\i. P i) \ P a" proof - have "CARD ('b) = 1" by (rule CARD_1) then obtain b :: 'b where "UNIV = {b}" by (auto iff: card_Suc_eq) then have "\P. (\i\UNIV. P i) \ P b" by auto then show thesis by (auto intro: that) qed fix x y :: "'a^'b::CARD_1" note [simp] = less_eq_vec_def less_vec_def all vec_eq_iff field_simps show "x \ y \ y \ x" by auto qed text\Constant Vectors\ definition "vec x = (\ i. x)" text\Also the scalar-vector multiplication.\ definition vector_scalar_mult:: "'a::times \ 'a ^ 'n \ 'a ^ 'n" (infixl "*s" 70) where "c *s x = (\ i. c * (x$i))" text \scalar product\ definition scalar_product :: "'a :: semiring_1 ^ 'n \ 'a ^ 'n \ 'a" where "scalar_product v w = (\ i \ UNIV. v $ i * w $ i)" subsection \Real vector space\ instantiation\<^marker>\tag unimportant\ vec :: (real_vector, finite) real_vector begin definition\<^marker>\tag important\ "scaleR \ (\ r x. (\ i. scaleR r (x$i)))" lemma vector_scaleR_component [simp]: "(scaleR r x)$i = scaleR r (x$i)" unfolding scaleR_vec_def by simp instance\<^marker>\tag unimportant\ by standard (simp_all add: vec_eq_iff scaleR_left_distrib scaleR_right_distrib) end subsection \Topological space\ instantiation\<^marker>\tag unimportant\ vec :: (topological_space, finite) topological_space begin definition\<^marker>\tag important\ [code del]: "open (S :: ('a ^ 'b) set) \ (\x\S. \A. (\i. open (A i) \ x$i \ A i) \ (\y. (\i. y$i \ A i) \ y \ S))" instance\<^marker>\tag unimportant\ proof show "open (UNIV :: ('a ^ 'b) set)" unfolding open_vec_def by auto next fix S T :: "('a ^ 'b) set" assume "open S" "open T" thus "open (S \ T)" unfolding open_vec_def apply clarify apply (drule (1) bspec)+ apply (clarify, rename_tac Sa Ta) apply (rule_tac x="\i. Sa i \ Ta i" in exI) apply (simp add: open_Int) done next fix K :: "('a ^ 'b) set set" assume "\S\K. open S" thus "open (\K)" unfolding open_vec_def - apply clarify - apply (drule (1) bspec) - apply (drule (1) bspec) - apply clarify - apply (rule_tac x=A in exI) - apply fast - done + by (metis Union_iff) qed end lemma open_vector_box: "\i. open (S i) \ open {x. \i. x $ i \ S i}" unfolding open_vec_def by auto lemma open_vimage_vec_nth: "open S \ open ((\x. x $ i) -` S)" unfolding open_vec_def apply clarify apply (rule_tac x="\k. if k = i then S else UNIV" in exI, simp) done lemma closed_vimage_vec_nth: "closed S \ closed ((\x. x $ i) -` S)" unfolding closed_open vimage_Compl [symmetric] by (rule open_vimage_vec_nth) lemma closed_vector_box: "\i. closed (S i) \ closed {x. \i. x $ i \ S i}" proof - have "{x. \i. x $ i \ S i} = (\i. (\x. x $ i) -` S i)" by auto thus "\i. closed (S i) \ closed {x. \i. x $ i \ S i}" by (simp add: closed_INT closed_vimage_vec_nth) qed lemma tendsto_vec_nth [tendsto_intros]: assumes "((\x. f x) \ a) net" shows "((\x. f x $ i) \ a $ i) net" proof (rule topological_tendstoI) fix S assume "open S" "a $ i \ S" then have "open ((\y. y $ i) -` S)" "a \ ((\y. y $ i) -` S)" by (simp_all add: open_vimage_vec_nth) with assms have "eventually (\x. f x \ (\y. y $ i) -` S) net" by (rule topological_tendstoD) then show "eventually (\x. f x $ i \ S) net" by simp qed lemma isCont_vec_nth [simp]: "isCont f a \ isCont (\x. f x $ i) a" unfolding isCont_def by (rule tendsto_vec_nth) lemma vec_tendstoI: assumes "\i. ((\x. f x $ i) \ a $ i) net" shows "((\x. f x) \ a) net" proof (rule topological_tendstoI) fix S assume "open S" and "a \ S" then obtain A where A: "\i. open (A i)" "\i. a $ i \ A i" and S: "\y. \i. y $ i \ A i \ y \ S" unfolding open_vec_def by metis have "\i. eventually (\x. f x $ i \ A i) net" using assms A by (rule topological_tendstoD) hence "eventually (\x. \i. f x $ i \ A i) net" by (rule eventually_all_finite) thus "eventually (\x. f x \ S) net" by (rule eventually_mono, simp add: S) qed lemma tendsto_vec_lambda [tendsto_intros]: assumes "\i. ((\x. f x i) \ a i) net" shows "((\x. \ i. f x i) \ (\ i. a i)) net" using assms by (simp add: vec_tendstoI) lemma open_image_vec_nth: assumes "open S" shows "open ((\x. x $ i) ` S)" proof (rule openI) fix a assume "a \ (\x. x $ i) ` S" then obtain z where "a = z $ i" and "z \ S" .. then obtain A where A: "\i. open (A i) \ z $ i \ A i" and S: "\y. (\i. y $ i \ A i) \ y \ S" using \open S\ unfolding open_vec_def by auto hence "A i \ (\x. x $ i) ` S" by (clarsimp, rule_tac x="\ j. if j = i then x else z $ j" in image_eqI, simp_all) hence "open (A i) \ a \ A i \ A i \ (\x. x $ i) ` S" using A \a = z $ i\ by simp then show "\T. open T \ a \ T \ T \ (\x. x $ i) ` S" by - (rule exI) qed instance\<^marker>\tag unimportant\ vec :: (perfect_space, finite) perfect_space proof fix x :: "'a ^ 'b" show "\ open {x}" proof assume "open {x}" hence "\i. open ((\x. x $ i) ` {x})" by (fast intro: open_image_vec_nth) hence "\i. open {x $ i}" by simp thus "False" by (simp add: not_open_singleton) qed qed subsection \Metric space\ (* TODO: Product of uniform spaces and compatibility with metric_spaces! *) instantiation\<^marker>\tag unimportant\ vec :: (metric_space, finite) dist begin definition\<^marker>\tag important\ "dist x y = L2_set (\i. dist (x$i) (y$i)) UNIV" instance .. end instantiation\<^marker>\tag unimportant\ vec :: (metric_space, finite) uniformity_dist begin definition\<^marker>\tag important\ [code del]: "(uniformity :: (('a^'b::_) \ ('a^'b::_)) filter) = (INF e\{0 <..}. principal {(x, y). dist x y < e})" instance\<^marker>\tag unimportant\ by standard (rule uniformity_vec_def) end declare uniformity_Abort[where 'a="'a :: metric_space ^ 'b :: finite", code] instantiation\<^marker>\tag unimportant\ vec :: (metric_space, finite) metric_space begin proposition dist_vec_nth_le: "dist (x $ i) (y $ i) \ dist x y" unfolding dist_vec_def by (rule member_le_L2_set) simp_all instance proof fix x y :: "'a ^ 'b" show "dist x y = 0 \ x = y" unfolding dist_vec_def by (simp add: L2_set_eq_0_iff vec_eq_iff) next fix x y z :: "'a ^ 'b" show "dist x y \ dist x z + dist y z" unfolding dist_vec_def apply (rule order_trans [OF _ L2_set_triangle_ineq]) apply (simp add: L2_set_mono dist_triangle2) done next fix S :: "('a ^ 'b) set" have *: "open S \ (\x\S. \e>0. \y. dist y x < e \ y \ S)" proof assume "open S" show "\x\S. \e>0. \y. dist y x < e \ y \ S" proof fix x assume "x \ S" obtain A where A: "\i. open (A i)" "\i. x $ i \ A i" and S: "\y. (\i. y $ i \ A i) \ y \ S" using \open S\ and \x \ S\ unfolding open_vec_def by metis have "\i\UNIV. \r>0. \y. dist y (x $ i) < r \ y \ A i" using A unfolding open_dist by simp hence "\r. \i\UNIV. 0 < r i \ (\y. dist y (x $ i) < r i \ y \ A i)" by (rule finite_set_choice [OF finite]) then obtain r where r1: "\i. 0 < r i" and r2: "\i y. dist y (x $ i) < r i \ y \ A i" by fast have "0 < Min (range r) \ (\y. dist y x < Min (range r) \ y \ S)" by (simp add: r1 r2 S le_less_trans [OF dist_vec_nth_le]) thus "\e>0. \y. dist y x < e \ y \ S" .. qed next assume *: "\x\S. \e>0. \y. dist y x < e \ y \ S" show "open S" proof (unfold open_vec_def, rule) fix x assume "x \ S" then obtain e where "0 < e" and S: "\y. dist y x < e \ y \ S" using * by fast define r where [abs_def]: "r i = e / sqrt (of_nat CARD('b))" for i :: 'b from \0 < e\ have r: "\i. 0 < r i" unfolding r_def by simp_all from \0 < e\ have e: "e = L2_set r UNIV" unfolding r_def by (simp add: L2_set_constant) define A where "A i = {y. dist (x $ i) y < r i}" for i have "\i. open (A i) \ x $ i \ A i" unfolding A_def by (simp add: open_ball r) moreover have "\y. (\i. y $ i \ A i) \ y \ S" by (simp add: A_def S dist_vec_def e L2_set_strict_mono dist_commute) ultimately show "\A. (\i. open (A i) \ x $ i \ A i) \ (\y. (\i. y $ i \ A i) \ y \ S)" by metis qed qed show "open S = (\x\S. \\<^sub>F (x', y) in uniformity. x' = x \ y \ S)" unfolding * eventually_uniformity_metric by (simp del: split_paired_All add: dist_vec_def dist_commute) qed end lemma Cauchy_vec_nth: "Cauchy (\n. X n) \ Cauchy (\n. X n $ i)" unfolding Cauchy_def by (fast intro: le_less_trans [OF dist_vec_nth_le]) lemma vec_CauchyI: fixes X :: "nat \ 'a::metric_space ^ 'n" assumes X: "\i. Cauchy (\n. X n $ i)" shows "Cauchy (\n. X n)" proof (rule metric_CauchyI) fix r :: real assume "0 < r" hence "0 < r / of_nat CARD('n)" (is "0 < ?s") by simp define N where "N i = (LEAST N. \m\N. \n\N. dist (X m $ i) (X n $ i) < ?s)" for i define M where "M = Max (range N)" have "\i. \N. \m\N. \n\N. dist (X m $ i) (X n $ i) < ?s" using X \0 < ?s\ by (rule metric_CauchyD) hence "\i. \m\N i. \n\N i. dist (X m $ i) (X n $ i) < ?s" unfolding N_def by (rule LeastI_ex) hence M: "\i. \m\M. \n\M. dist (X m $ i) (X n $ i) < ?s" unfolding M_def by simp { fix m n :: nat assume "M \ m" "M \ n" have "dist (X m) (X n) = L2_set (\i. dist (X m $ i) (X n $ i)) UNIV" unfolding dist_vec_def .. also have "\ \ sum (\i. dist (X m $ i) (X n $ i)) UNIV" by (rule L2_set_le_sum [OF zero_le_dist]) also have "\ < sum (\i::'n. ?s) UNIV" by (rule sum_strict_mono, simp_all add: M \M \ m\ \M \ n\) also have "\ = r" by simp finally have "dist (X m) (X n) < r" . } hence "\m\M. \n\M. dist (X m) (X n) < r" by simp then show "\M. \m\M. \n\M. dist (X m) (X n) < r" .. qed instance\<^marker>\tag unimportant\ vec :: (complete_space, finite) complete_space proof fix X :: "nat \ 'a ^ 'b" assume "Cauchy X" have "\i. (\n. X n $ i) \ lim (\n. X n $ i)" using Cauchy_vec_nth [OF \Cauchy X\] by (simp add: Cauchy_convergent_iff convergent_LIMSEQ_iff) hence "X \ vec_lambda (\i. lim (\n. X n $ i))" by (simp add: vec_tendstoI) then show "convergent X" by (rule convergentI) qed subsection \Normed vector space\ instantiation\<^marker>\tag unimportant\ vec :: (real_normed_vector, finite) real_normed_vector begin definition\<^marker>\tag important\ "norm x = L2_set (\i. norm (x$i)) UNIV" definition\<^marker>\tag important\ "sgn (x::'a^'b) = scaleR (inverse (norm x)) x" instance\<^marker>\tag unimportant\ proof fix a :: real and x y :: "'a ^ 'b" show "norm x = 0 \ x = 0" unfolding norm_vec_def by (simp add: L2_set_eq_0_iff vec_eq_iff) show "norm (x + y) \ norm x + norm y" unfolding norm_vec_def apply (rule order_trans [OF _ L2_set_triangle_ineq]) apply (simp add: L2_set_mono norm_triangle_ineq) done show "norm (scaleR a x) = \a\ * norm x" unfolding norm_vec_def by (simp add: L2_set_right_distrib) show "sgn x = scaleR (inverse (norm x)) x" by (rule sgn_vec_def) show "dist x y = norm (x - y)" unfolding dist_vec_def norm_vec_def by (simp add: dist_norm) qed end lemma norm_nth_le: "norm (x $ i) \ norm x" unfolding norm_vec_def by (rule member_le_L2_set) simp_all lemma norm_le_componentwise_cart: fixes x :: "'a::real_normed_vector^'n" assumes "\i. norm(x$i) \ norm(y$i)" shows "norm x \ norm y" unfolding norm_vec_def by (rule L2_set_mono) (auto simp: assms) lemma component_le_norm_cart: "\x$i\ \ norm x" - apply (simp add: norm_vec_def) - apply (rule member_le_L2_set, simp_all) - done + by (metis norm_nth_le real_norm_def) lemma norm_bound_component_le_cart: "norm x \ e ==> \x$i\ \ e" by (metis component_le_norm_cart order_trans) lemma norm_bound_component_lt_cart: "norm x < e ==> \x$i\ < e" by (metis component_le_norm_cart le_less_trans) lemma norm_le_l1_cart: "norm x \ sum(\i. \x$i\) UNIV" by (simp add: norm_vec_def L2_set_le_sum) lemma bounded_linear_vec_nth[intro]: "bounded_linear (\x. x $ i)" -apply standard -apply (rule vector_add_component) -apply (rule vector_scaleR_component) -apply (rule_tac x="1" in exI, simp add: norm_nth_le) -done +proof + show "\K. \x. norm (x $ i) \ norm x * K" + by (metis mult.commute mult.left_neutral norm_nth_le) +qed auto instance vec :: (banach, finite) banach .. subsection \Inner product space\ instantiation\<^marker>\tag unimportant\ vec :: (real_inner, finite) real_inner begin definition\<^marker>\tag important\ "inner x y = sum (\i. inner (x$i) (y$i)) UNIV" instance\<^marker>\tag unimportant\ proof fix r :: real and x y z :: "'a ^ 'b" show "inner x y = inner y x" unfolding inner_vec_def by (simp add: inner_commute) show "inner (x + y) z = inner x z + inner y z" unfolding inner_vec_def by (simp add: inner_add_left sum.distrib) show "inner (scaleR r x) y = r * inner x y" unfolding inner_vec_def by (simp add: sum_distrib_left) show "0 \ inner x x" unfolding inner_vec_def by (simp add: sum_nonneg) show "inner x x = 0 \ x = 0" unfolding inner_vec_def by (simp add: vec_eq_iff sum_nonneg_eq_0_iff) show "norm x = sqrt (inner x x)" unfolding inner_vec_def norm_vec_def L2_set_def by (simp add: power2_norm_eq_inner) qed end subsection \Euclidean space\ text \Vectors pointing along a single axis.\ definition\<^marker>\tag important\ "axis k x = (\ i. if i = k then x else 0)" lemma axis_nth [simp]: "axis i x $ i = x" unfolding axis_def by simp lemma axis_eq_axis: "axis i x = axis j y \ x = y \ i = j \ x = 0 \ y = 0" unfolding axis_def vec_eq_iff by auto lemma inner_axis_axis: "inner (axis i x) (axis j y) = (if i = j then inner x y else 0)" - unfolding inner_vec_def - apply (cases "i = j") - apply clarsimp - apply (subst sum.remove [of _ j], simp_all) - apply (rule sum.neutral, simp add: axis_def) - apply (rule sum.neutral, simp add: axis_def) - done + by (simp add: inner_vec_def axis_def sum.neutral sum.remove [of _ j]) lemma inner_axis: "inner x (axis i y) = inner (x $ i) y" by (simp add: inner_vec_def axis_def sum.remove [where x=i]) lemma inner_axis': "inner(axis i y) x = inner y (x $ i)" by (simp add: inner_axis inner_commute) instantiation\<^marker>\tag unimportant\ vec :: (euclidean_space, finite) euclidean_space begin definition\<^marker>\tag important\ "Basis = (\i. \u\Basis. {axis i u})" instance\<^marker>\tag unimportant\ proof show "(Basis :: ('a ^ 'b) set) \ {}" unfolding Basis_vec_def by simp next show "finite (Basis :: ('a ^ 'b) set)" unfolding Basis_vec_def by simp next fix u v :: "'a ^ 'b" assume "u \ Basis" and "v \ Basis" thus "inner u v = (if u = v then 1 else 0)" unfolding Basis_vec_def by (auto simp add: inner_axis_axis axis_eq_axis inner_Basis) next fix x :: "'a ^ 'b" show "(\u\Basis. inner x u = 0) \ x = 0" unfolding Basis_vec_def by (simp add: inner_axis euclidean_all_zero_iff vec_eq_iff) qed proposition DIM_cart [simp]: "DIM('a^'b) = CARD('b) * DIM('a)" proof - have "card (\i::'b. \u::'a\Basis. {axis i u}) = (\i::'b\UNIV. card (\u::'a\Basis. {axis i u}))" by (rule card_UN_disjoint) (auto simp: axis_eq_axis) also have "... = CARD('b) * DIM('a)" by (subst card_UN_disjoint) (auto simp: axis_eq_axis) finally show ?thesis by (simp add: Basis_vec_def) qed end lemma norm_axis_1 [simp]: "norm (axis m (1::real)) = 1" by (simp add: inner_axis' norm_eq_1) lemma sum_norm_allsubsets_bound_cart: fixes f:: "'a \ real ^'n" assumes fP: "finite P" and fPs: "\Q. Q \ P \ norm (sum f Q) \ e" shows "sum (\x. norm (f x)) P \ 2 * real CARD('n) * e" using sum_norm_allsubsets_bound[OF assms] by simp lemma cart_eq_inner_axis: "a $ i = inner a (axis i 1)" by (simp add: inner_axis) lemma axis_eq_0_iff [simp]: shows "axis m x = 0 \ x = 0" by (simp add: axis_def vec_eq_iff) lemma axis_in_Basis_iff [simp]: "axis i a \ Basis \ a \ Basis" by (auto simp: Basis_vec_def axis_eq_axis) text\Mapping each basis element to the corresponding finite index\ definition axis_index :: "('a::comm_ring_1)^'n \ 'n" where "axis_index v \ SOME i. v = axis i 1" lemma axis_inverse: fixes v :: "real^'n" assumes "v \ Basis" shows "\i. v = axis i 1" proof - have "v \ (\n. \r\Basis. {axis n r})" using assms Basis_vec_def by blast then show ?thesis by (force simp add: vec_eq_iff) qed lemma axis_index: fixes v :: "real^'n" assumes "v \ Basis" shows "v = axis (axis_index v) 1" by (metis (mono_tags) assms axis_inverse axis_index_def someI_ex) lemma axis_index_axis [simp]: fixes UU :: "real^'n" shows "(axis_index (axis u 1 :: real^'n)) = (u::'n)" by (simp add: axis_eq_axis axis_index_def) subsection\<^marker>\tag unimportant\ \A naive proof procedure to lift really trivial arithmetic stuff from the basis of the vector space\ lemma sum_cong_aux: "(\x. x \ A \ f x = g x) \ sum f A = sum g A" by (auto intro: sum.cong) hide_fact (open) sum_cong_aux method_setup vector = \ let val ss1 = simpset_of (put_simpset HOL_basic_ss \<^context> addsimps [@{thm sum.distrib} RS sym, @{thm sum_subtractf} RS sym, @{thm sum_distrib_left}, @{thm sum_distrib_right}, @{thm sum_negf} RS sym]) val ss2 = simpset_of (\<^context> addsimps [@{thm plus_vec_def}, @{thm times_vec_def}, @{thm minus_vec_def}, @{thm uminus_vec_def}, @{thm one_vec_def}, @{thm zero_vec_def}, @{thm vec_def}, @{thm scaleR_vec_def}, @{thm vector_scalar_mult_def}]) fun vector_arith_tac ctxt ths = simp_tac (put_simpset ss1 ctxt) THEN' (fn i => resolve_tac ctxt @{thms Finite_Cartesian_Product.sum_cong_aux} i ORELSE resolve_tac ctxt @{thms sum.neutral} i ORELSE simp_tac (put_simpset HOL_basic_ss ctxt addsimps [@{thm vec_eq_iff}]) i) (* THEN' TRY o clarify_tac HOL_cs THEN' (TRY o rtac @{thm iffI}) *) THEN' asm_full_simp_tac (put_simpset ss2 ctxt addsimps ths) in Attrib.thms >> (fn ths => fn ctxt => SIMPLE_METHOD' (vector_arith_tac ctxt ths)) end \ "lift trivial vector statements to real arith statements" lemma vec_0[simp]: "vec 0 = 0" by vector lemma vec_1[simp]: "vec 1 = 1" by vector lemma vec_inj[simp]: "vec x = vec y \ x = y" by vector lemma vec_in_image_vec: "vec x \ (vec ` S) \ x \ S" by auto lemma vec_add: "vec(x + y) = vec x + vec y" by vector lemma vec_sub: "vec(x - y) = vec x - vec y" by vector lemma vec_cmul: "vec(c * x) = c *s vec x " by vector lemma vec_neg: "vec(- x) = - vec x " by vector lemma vec_scaleR: "vec(c * x) = c *\<^sub>R vec x" by vector lemma vec_sum: assumes "finite S" shows "vec(sum f S) = sum (vec \ f) S" using assms proof induct case empty then show ?case by simp next case insert then show ?case by (auto simp add: vec_add) qed text\Obvious "component-pushing".\ lemma vec_component [simp]: "vec x $ i = x" by vector lemma vector_mult_component [simp]: "(x * y)$i = x$i * y$i" by vector lemma vector_smult_component [simp]: "(c *s y)$i = c * (y$i)" by vector lemma cond_component: "(if b then x else y)$i = (if b then x$i else y$i)" by vector lemmas\<^marker>\tag unimportant\ vector_component = vec_component vector_add_component vector_mult_component vector_smult_component vector_minus_component vector_uminus_component vector_scaleR_component cond_component subsection\<^marker>\tag unimportant\ \Some frequently useful arithmetic lemmas over vectors\ instance vec :: (semigroup_mult, finite) semigroup_mult by standard (vector mult.assoc) instance vec :: (monoid_mult, finite) monoid_mult by standard vector+ instance vec :: (ab_semigroup_mult, finite) ab_semigroup_mult by standard (vector mult.commute) instance vec :: (comm_monoid_mult, finite) comm_monoid_mult by standard vector instance vec :: (semiring, finite) semiring by standard (vector field_simps)+ instance vec :: (semiring_0, finite) semiring_0 by standard (vector field_simps)+ instance vec :: (semiring_1, finite) semiring_1 by standard vector instance vec :: (comm_semiring, finite) comm_semiring by standard (vector field_simps)+ instance vec :: (comm_semiring_0, finite) comm_semiring_0 .. instance vec :: (semiring_0_cancel, finite) semiring_0_cancel .. instance vec :: (comm_semiring_0_cancel, finite) comm_semiring_0_cancel .. instance vec :: (ring, finite) ring .. instance vec :: (semiring_1_cancel, finite) semiring_1_cancel .. instance vec :: (comm_semiring_1, finite) comm_semiring_1 .. instance vec :: (ring_1, finite) ring_1 .. instance vec :: (real_algebra, finite) real_algebra by standard (simp_all add: vec_eq_iff) instance vec :: (real_algebra_1, finite) real_algebra_1 .. lemma of_nat_index: "(of_nat n :: 'a::semiring_1 ^'n)$i = of_nat n" proof (induct n) case 0 then show ?case by vector next case Suc then show ?case by vector qed lemma one_index [simp]: "(1 :: 'a :: one ^ 'n) $ i = 1" by vector lemma neg_one_index [simp]: "(- 1 :: 'a :: {one, uminus} ^ 'n) $ i = - 1" by vector instance vec :: (semiring_char_0, finite) semiring_char_0 proof fix m n :: nat show "inj (of_nat :: nat \ 'a ^ 'b)" by (auto intro!: injI simp add: vec_eq_iff of_nat_index) qed instance vec :: (numeral, finite) numeral .. instance vec :: (semiring_numeral, finite) semiring_numeral .. lemma numeral_index [simp]: "numeral w $ i = numeral w" by (induct w) (simp_all only: numeral.simps vector_add_component one_index) lemma neg_numeral_index [simp]: "- numeral w $ i = - numeral w" by (simp only: vector_uminus_component numeral_index) instance vec :: (comm_ring_1, finite) comm_ring_1 .. instance vec :: (ring_char_0, finite) ring_char_0 .. lemma vector_smult_assoc: "a *s (b *s x) = ((a::'a::semigroup_mult) * b) *s x" by (vector mult.assoc) lemma vector_sadd_rdistrib: "((a::'a::semiring) + b) *s x = a *s x + b *s x" by (vector field_simps) lemma vector_add_ldistrib: "(c::'a::semiring) *s (x + y) = c *s x + c *s y" by (vector field_simps) lemma vector_smult_lzero[simp]: "(0::'a::mult_zero) *s x = 0" by vector lemma vector_smult_lid[simp]: "(1::'a::monoid_mult) *s x = x" by vector lemma vector_ssub_ldistrib: "(c::'a::ring) *s (x - y) = c *s x - c *s y" by (vector field_simps) lemma vector_smult_rneg: "(c::'a::ring) *s -x = -(c *s x)" by vector lemma vector_smult_lneg: "- (c::'a::ring) *s x = -(c *s x)" by vector lemma vector_sneg_minus1: "-x = (-1::'a::ring_1) *s x" by vector lemma vector_smult_rzero[simp]: "c *s 0 = (0::'a::mult_zero ^ 'n)" by vector lemma vector_sub_rdistrib: "((a::'a::ring) - b) *s x = a *s x - b *s x" by (vector field_simps) lemma vec_eq[simp]: "(vec m = vec n) \ (m = n)" by (simp add: vec_eq_iff) lemma Vector_Spaces_linear_vec [simp]: "Vector_Spaces.linear (*) vector_scalar_mult vec" by unfold_locales (vector algebra_simps)+ lemma vector_mul_eq_0[simp]: "(a *s x = 0) \ a = (0::'a::idom) \ x = 0" by vector lemma vector_mul_lcancel[simp]: "a *s x = a *s y \ a = (0::'a::field) \ x = y" by (metis eq_iff_diff_eq_0 vector_mul_eq_0 vector_ssub_ldistrib) lemma vector_mul_rcancel[simp]: "a *s x = b *s x \ (a::'a::field) = b \ x = 0" by (subst eq_iff_diff_eq_0, subst vector_sub_rdistrib [symmetric]) simp lemma scalar_mult_eq_scaleR [abs_def]: "c *s x = c *\<^sub>R x" unfolding scaleR_vec_def vector_scalar_mult_def by simp lemma dist_mul[simp]: "dist (c *s x) (c *s y) = \c\ * dist x y" unfolding dist_norm scalar_mult_eq_scaleR unfolding scaleR_right_diff_distrib[symmetric] by simp lemma sum_component [simp]: fixes f:: " 'a \ ('b::comm_monoid_add) ^'n" shows "(sum f S)$i = sum (\x. (f x)$i) S" proof (cases "finite S") case True then show ?thesis by induct simp_all next case False then show ?thesis by simp qed lemma sum_eq: "sum f S = (\ i. sum (\x. (f x)$i ) S)" by (simp add: vec_eq_iff) lemma sum_cmul: fixes f:: "'c \ ('a::semiring_1)^'n" shows "sum (\x. c *s f x) S = c *s sum f S" by (simp add: vec_eq_iff sum_distrib_left) lemma linear_vec [simp]: "linear vec" using Vector_Spaces_linear_vec - apply (auto ) by unfold_locales (vector algebra_simps)+ subsection \Matrix operations\ text\Matrix notation. NB: an MxN matrix is of type \<^typ>\'a^'n^'m\, not \<^typ>\'a^'m^'n\\ definition\<^marker>\tag important\ map_matrix::"('a \ 'b) \ (('a, 'i::finite)vec, 'j::finite) vec \ (('b, 'i)vec, 'j) vec" where "map_matrix f x = (\ i j. f (x $ i $ j))" lemma nth_map_matrix[simp]: "map_matrix f x $ i $ j = f (x $ i $ j)" by (simp add: map_matrix_def) definition\<^marker>\tag important\ matrix_matrix_mult :: "('a::semiring_1) ^'n^'m \ 'a ^'p^'n \ 'a ^ 'p ^'m" (infixl "**" 70) where "m ** m' == (\ i j. sum (\k. ((m$i)$k) * ((m'$k)$j)) (UNIV :: 'n set)) ::'a ^ 'p ^'m" definition\<^marker>\tag important\ matrix_vector_mult :: "('a::semiring_1) ^'n^'m \ 'a ^'n \ 'a ^ 'm" (infixl "*v" 70) where "m *v x \ (\ i. sum (\j. ((m$i)$j) * (x$j)) (UNIV ::'n set)) :: 'a^'m" definition\<^marker>\tag important\ vector_matrix_mult :: "'a ^ 'm \ ('a::semiring_1) ^'n^'m \ 'a ^'n " (infixl "v*" 70) where "v v* m == (\ j. sum (\i. ((m$i)$j) * (v$i)) (UNIV :: 'm set)) :: 'a^'n" definition\<^marker>\tag unimportant\ "(mat::'a::zero => 'a ^'n^'n) k = (\ i j. if i = j then k else 0)" definition\<^marker>\tag unimportant\ transpose where "(transpose::'a^'n^'m \ 'a^'m^'n) A = (\ i j. ((A$j)$i))" definition\<^marker>\tag unimportant\ "(row::'m => 'a ^'n^'m \ 'a ^'n) i A = (\ j. ((A$i)$j))" definition\<^marker>\tag unimportant\ "(column::'n =>'a^'n^'m =>'a^'m) j A = (\ i. ((A$i)$j))" definition\<^marker>\tag unimportant\ "rows(A::'a^'n^'m) = { row i A | i. i \ (UNIV :: 'm set)}" definition\<^marker>\tag unimportant\ "columns(A::'a^'n^'m) = { column i A | i. i \ (UNIV :: 'n set)}" lemma times0_left [simp]: "(0::'a::semiring_1^'n^'m) ** (A::'a ^'p^'n) = 0" by (simp add: matrix_matrix_mult_def zero_vec_def) lemma times0_right [simp]: "(A::'a::semiring_1^'n^'m) ** (0::'a ^'p^'n) = 0" by (simp add: matrix_matrix_mult_def zero_vec_def) lemma mat_0[simp]: "mat 0 = 0" by (vector mat_def) lemma matrix_add_ldistrib: "(A ** (B + C)) = (A ** B) + (A ** C)" by (vector matrix_matrix_mult_def sum.distrib[symmetric] field_simps) lemma matrix_mul_lid [simp]: fixes A :: "'a::semiring_1 ^ 'm ^ 'n" shows "mat 1 ** A = A" - apply (simp add: matrix_matrix_mult_def mat_def) - apply vector - apply (auto simp only: if_distrib if_distribR sum.delta'[OF finite] - mult_1_left mult_zero_left if_True UNIV_I) - done + unfolding matrix_matrix_mult_def mat_def + by (auto simp: if_distrib if_distribR sum.delta'[OF finite] cong: if_cong) lemma matrix_mul_rid [simp]: fixes A :: "'a::semiring_1 ^ 'm ^ 'n" shows "A ** mat 1 = A" - apply (simp add: matrix_matrix_mult_def mat_def) - apply vector - apply (auto simp only: if_distrib if_distribR sum.delta[OF finite] - mult_1_right mult_zero_right if_True UNIV_I cong: if_cong) - done + unfolding matrix_matrix_mult_def mat_def + by (auto simp: if_distrib if_distribR sum.delta'[OF finite] cong: if_cong) proposition matrix_mul_assoc: "A ** (B ** C) = (A ** B) ** C" apply (vector matrix_matrix_mult_def sum_distrib_left sum_distrib_right mult.assoc) apply (subst sum.swap) apply simp done proposition matrix_vector_mul_assoc: "A *v (B *v x) = (A ** B) *v x" apply (vector matrix_matrix_mult_def matrix_vector_mult_def sum_distrib_left sum_distrib_right mult.assoc) apply (subst sum.swap) apply simp done proposition scalar_matrix_assoc: fixes A :: "('a::real_algebra_1)^'m^'n" shows "k *\<^sub>R (A ** B) = (k *\<^sub>R A) ** B" by (simp add: matrix_matrix_mult_def sum_distrib_left mult_ac vec_eq_iff scaleR_sum_right) proposition matrix_scalar_ac: fixes A :: "('a::real_algebra_1)^'m^'n" shows "A ** (k *\<^sub>R B) = k *\<^sub>R A ** B" by (simp add: matrix_matrix_mult_def sum_distrib_left mult_ac vec_eq_iff) lemma matrix_vector_mul_lid [simp]: "mat 1 *v x = (x::'a::semiring_1 ^ 'n)" apply (vector matrix_vector_mult_def mat_def) apply (simp add: if_distrib if_distribR cong del: if_weak_cong) done lemma matrix_transpose_mul: "transpose(A ** B) = transpose B ** transpose (A::'a::comm_semiring_1^_^_)" by (simp add: matrix_matrix_mult_def transpose_def vec_eq_iff mult.commute) lemma matrix_mult_transpose_dot_column: shows "transpose A ** A = (\ i j. inner (column i A) (column j A))" by (simp add: matrix_matrix_mult_def vec_eq_iff transpose_def column_def inner_vec_def) lemma matrix_mult_transpose_dot_row: shows "A ** transpose A = (\ i j. inner (row i A) (row j A))" by (simp add: matrix_matrix_mult_def vec_eq_iff transpose_def row_def inner_vec_def) lemma matrix_eq: fixes A B :: "'a::semiring_1 ^ 'n ^ 'm" - shows "A = B \ (\x. A *v x = B *v x)" (is "?lhs \ ?rhs") - apply auto - apply (subst vec_eq_iff) - apply clarify - apply (clarsimp simp add: matrix_vector_mult_def if_distrib if_distribR vec_eq_iff cong del: if_weak_cong) - apply (erule_tac x="axis ia 1" in allE) - apply (erule_tac x="i" in allE) - apply (auto simp add: if_distrib if_distribR axis_def - sum.delta[OF finite] cong del: if_weak_cong) - done + shows "A = B \ (\x. A *v x = B *v x)" (is "?lhs \ ?rhs") +proof + assume ?rhs + then show ?lhs + apply (subst vec_eq_iff) + apply (clarsimp simp add: matrix_vector_mult_def if_distrib if_distribR vec_eq_iff cong: if_cong) + apply (erule_tac x="axis ia 1" in allE) + apply (erule_tac x="i" in allE) + apply (auto simp add: if_distrib if_distribR axis_def + sum.delta[OF finite] cong del: if_weak_cong) + done +qed auto lemma matrix_vector_mul_component: "(A *v x)$k = inner (A$k) x" by (simp add: matrix_vector_mult_def inner_vec_def) lemma dot_lmul_matrix: "inner ((x::real ^_) v* A) y = inner x (A *v y)" apply (simp add: inner_vec_def matrix_vector_mult_def vector_matrix_mult_def sum_distrib_right sum_distrib_left ac_simps) apply (subst sum.swap) apply simp done lemma transpose_mat [simp]: "transpose (mat n) = mat n" by (vector transpose_def mat_def) lemma transpose_transpose [simp]: "transpose(transpose A) = A" by (vector transpose_def) lemma row_transpose [simp]: "row i (transpose A) = column i A" by (simp add: row_def column_def transpose_def vec_eq_iff) lemma column_transpose [simp]: "column i (transpose A) = row i A" by (simp add: row_def column_def transpose_def vec_eq_iff) lemma rows_transpose [simp]: "rows(transpose A) = columns A" by (auto simp add: rows_def columns_def intro: set_eqI) lemma columns_transpose [simp]: "columns(transpose A) = rows A" by (metis transpose_transpose rows_transpose) lemma transpose_scalar: "transpose (k *\<^sub>R A) = k *\<^sub>R transpose A" unfolding transpose_def by (simp add: vec_eq_iff) lemma transpose_iff [iff]: "transpose A = transpose B \ A = B" by (metis transpose_transpose) lemma matrix_mult_sum: "(A::'a::comm_semiring_1^'n^'m) *v x = sum (\i. (x$i) *s column i A) (UNIV:: 'n set)" by (simp add: matrix_vector_mult_def vec_eq_iff column_def mult.commute) lemma vector_componentwise: "(x::'a::ring_1^'n) = (\ j. \i\UNIV. (x$i) * (axis i 1 :: 'a^'n) $ j)" by (simp add: axis_def if_distrib sum.If_cases vec_eq_iff) lemma basis_expansion: "sum (\i. (x$i) *s axis i 1) UNIV = (x::('a::ring_1) ^'n)" by (auto simp add: axis_def vec_eq_iff if_distrib sum.If_cases cong del: if_weak_cong) text\Correspondence between matrices and linear operators.\ definition\<^marker>\tag important\ matrix :: "('a::{plus,times, one, zero}^'m \ 'a ^ 'n) \ 'a^'m^'n" where "matrix f = (\ i j. (f(axis j 1))$i)" lemma matrix_id_mat_1: "matrix id = mat 1" by (simp add: mat_def matrix_def axis_def) lemma matrix_scaleR: "(matrix ((*\<^sub>R) r)) = mat r" by (simp add: mat_def matrix_def axis_def if_distrib cong: if_cong) lemma matrix_vector_mul_linear[intro, simp]: "linear (\x. A *v (x::'a::real_algebra_1 ^ _))" by (simp add: linear_iff matrix_vector_mult_def vec_eq_iff field_simps sum_distrib_left sum.distrib scaleR_right.sum) lemma vector_matrix_left_distrib [algebra_simps]: shows "(x + y) v* A = x v* A + y v* A" unfolding vector_matrix_mult_def by (simp add: algebra_simps sum.distrib vec_eq_iff) lemma matrix_vector_right_distrib [algebra_simps]: "A *v (x + y) = A *v x + A *v y" by (vector matrix_vector_mult_def sum.distrib distrib_left) lemma matrix_vector_mult_diff_distrib [algebra_simps]: fixes A :: "'a::ring_1^'n^'m" shows "A *v (x - y) = A *v x - A *v y" by (vector matrix_vector_mult_def sum_subtractf right_diff_distrib) lemma matrix_vector_mult_scaleR[algebra_simps]: fixes A :: "real^'n^'m" shows "A *v (c *\<^sub>R x) = c *\<^sub>R (A *v x)" using linear_iff matrix_vector_mul_linear by blast lemma matrix_vector_mult_0_right [simp]: "A *v 0 = 0" by (simp add: matrix_vector_mult_def vec_eq_iff) lemma matrix_vector_mult_0 [simp]: "0 *v w = 0" by (simp add: matrix_vector_mult_def vec_eq_iff) lemma matrix_vector_mult_add_rdistrib [algebra_simps]: "(A + B) *v x = (A *v x) + (B *v x)" by (vector matrix_vector_mult_def sum.distrib distrib_right) lemma matrix_vector_mult_diff_rdistrib [algebra_simps]: fixes A :: "'a :: ring_1^'n^'m" shows "(A - B) *v x = (A *v x) - (B *v x)" by (vector matrix_vector_mult_def sum_subtractf left_diff_distrib) lemma matrix_vector_column: "(A::'a::comm_semiring_1^'n^_) *v x = sum (\i. (x$i) *s ((transpose A)$i)) (UNIV:: 'n set)" by (simp add: matrix_vector_mult_def transpose_def vec_eq_iff mult.commute) subsection\Inverse matrices (not necessarily square)\ definition\<^marker>\tag important\ "invertible(A::'a::semiring_1^'n^'m) \ (\A'::'a^'m^'n. A ** A' = mat 1 \ A' ** A = mat 1)" definition\<^marker>\tag important\ "matrix_inv(A:: 'a::semiring_1^'n^'m) = (SOME A'::'a^'m^'n. A ** A' = mat 1 \ A' ** A = mat 1)" lemma inj_matrix_vector_mult: fixes A::"'a::field^'n^'m" assumes "invertible A" shows "inj ((*v) A)" by (metis assms inj_on_inverseI invertible_def matrix_vector_mul_assoc matrix_vector_mul_lid) lemma scalar_invertible: fixes A :: "('a::real_algebra_1)^'m^'n" assumes "k \ 0" and "invertible A" shows "invertible (k *\<^sub>R A)" proof - obtain A' where "A ** A' = mat 1" and "A' ** A = mat 1" using assms unfolding invertible_def by auto with \k \ 0\ have "(k *\<^sub>R A) ** ((1/k) *\<^sub>R A') = mat 1" "((1/k) *\<^sub>R A') ** (k *\<^sub>R A) = mat 1" by (simp_all add: assms matrix_scalar_ac) thus "invertible (k *\<^sub>R A)" unfolding invertible_def by auto qed proposition scalar_invertible_iff: fixes A :: "('a::real_algebra_1)^'m^'n" assumes "k \ 0" and "invertible A" shows "invertible (k *\<^sub>R A) \ k \ 0 \ invertible A" by (simp add: assms scalar_invertible) lemma vector_transpose_matrix [simp]: "x v* transpose A = A *v x" unfolding transpose_def vector_matrix_mult_def matrix_vector_mult_def by simp lemma transpose_matrix_vector [simp]: "transpose A *v x = x v* A" unfolding transpose_def vector_matrix_mult_def matrix_vector_mult_def by simp lemma vector_scalar_commute: fixes A :: "'a::{field}^'m^'n" shows "A *v (c *s x) = c *s (A *v x)" by (simp add: vector_scalar_mult_def matrix_vector_mult_def mult_ac sum_distrib_left) lemma scalar_vector_matrix_assoc: fixes k :: "'a::{field}" and x :: "'a::{field}^'n" and A :: "'a^'m^'n" shows "(k *s x) v* A = k *s (x v* A)" by (metis transpose_matrix_vector vector_scalar_commute) lemma vector_matrix_mult_0 [simp]: "0 v* A = 0" unfolding vector_matrix_mult_def by (simp add: zero_vec_def) lemma vector_matrix_mult_0_right [simp]: "x v* 0 = 0" unfolding vector_matrix_mult_def by (simp add: zero_vec_def) lemma vector_matrix_mul_rid [simp]: fixes v :: "('a::semiring_1)^'n" shows "v v* mat 1 = v" by (metis matrix_vector_mul_lid transpose_mat vector_transpose_matrix) lemma scaleR_vector_matrix_assoc: fixes k :: real and x :: "real^'n" and A :: "real^'m^'n" shows "(k *\<^sub>R x) v* A = k *\<^sub>R (x v* A)" by (metis matrix_vector_mult_scaleR transpose_matrix_vector) proposition vector_scaleR_matrix_ac: fixes k :: real and x :: "real^'n" and A :: "real^'m^'n" shows "x v* (k *\<^sub>R A) = k *\<^sub>R (x v* A)" proof - have "x v* (k *\<^sub>R A) = (k *\<^sub>R x) v* A" unfolding vector_matrix_mult_def by (simp add: algebra_simps) with scaleR_vector_matrix_assoc show "x v* (k *\<^sub>R A) = k *\<^sub>R (x v* A)" by auto qed end