# HG changeset patch # User wenzelm # Date 1469216636 -7200 # Node ID c2f69dac03535fe0be00c111a69ec992d97a7549 # Parent e0cd6469a6b84e744c52617c9a767404def4e968 misc tuning and modernization; diff -r e0cd6469a6b8 -r c2f69dac0353 src/HOL/Real_Vector_Spaces.thy --- a/src/HOL/Real_Vector_Spaces.thy Fri Jul 22 19:04:30 2016 +0200 +++ b/src/HOL/Real_Vector_Spaces.thy Fri Jul 22 21:43:56 2016 +0200 @@ -34,39 +34,36 @@ using add [of x "- y"] by (simp add: minus) lemma setsum: "f (setsum g A) = (\x\A. f (g x))" -apply (cases "finite A") -apply (induct set: finite) -apply (simp add: zero) -apply (simp add: add) -apply (simp add: zero) -done + apply (cases "finite A") + apply (induct set: finite) + apply (simp add: zero) + apply (simp add: add) + apply (simp add: zero) + done end + subsection \Vector spaces\ locale vector_space = fixes scale :: "'a::field \ 'b::ab_group_add \ 'b" - assumes scale_right_distrib [algebra_simps]: - "scale a (x + y) = scale a x + scale a y" - and scale_left_distrib [algebra_simps]: - "scale (a + b) x = scale a x + scale b x" - and scale_scale [simp]: "scale a (scale b x) = scale (a * b) x" - and scale_one [simp]: "scale 1 x = x" + assumes scale_right_distrib [algebra_simps]: "scale a (x + y) = scale a x + scale a y" + and scale_left_distrib [algebra_simps]: "scale (a + b) x = scale a x + scale b x" + and scale_scale [simp]: "scale a (scale b x) = scale (a * b) x" + and scale_one [simp]: "scale 1 x = x" begin -lemma scale_left_commute: - "scale a (scale b x) = scale b (scale a x)" -by (simp add: mult.commute) +lemma scale_left_commute: "scale a (scale b x) = scale b (scale a x)" + by (simp add: mult.commute) lemma scale_zero_left [simp]: "scale 0 x = 0" and scale_minus_left [simp]: "scale (- a) x = - (scale a x)" - and scale_left_diff_distrib [algebra_simps]: - "scale (a - b) x = scale a x - scale b x" + and scale_left_diff_distrib [algebra_simps]: "scale (a - b) x = scale a x - scale b x" and scale_setsum_left: "scale (setsum f A) x = (\a\A. scale (f a) x)" proof - interpret s: additive "\a. scale a x" - proof qed (rule scale_left_distrib) + by standard (rule scale_left_distrib) show "scale 0 x = 0" by (rule s.zero) show "scale (- a) x = - (scale a x)" by (rule s.minus) show "scale (a - b) x = scale a x - scale b x" by (rule s.diff) @@ -75,72 +72,70 @@ lemma scale_zero_right [simp]: "scale a 0 = 0" and scale_minus_right [simp]: "scale a (- x) = - (scale a x)" - and scale_right_diff_distrib [algebra_simps]: - "scale a (x - y) = scale a x - scale a y" + and scale_right_diff_distrib [algebra_simps]: "scale a (x - y) = scale a x - scale a y" and scale_setsum_right: "scale a (setsum f A) = (\x\A. scale a (f x))" proof - interpret s: additive "\x. scale a x" - proof qed (rule scale_right_distrib) + by standard (rule scale_right_distrib) show "scale a 0 = 0" by (rule s.zero) show "scale a (- x) = - (scale a x)" by (rule s.minus) show "scale a (x - y) = scale a x - scale a y" by (rule s.diff) show "scale a (setsum f A) = (\x\A. scale a (f x))" by (rule s.setsum) qed -lemma scale_eq_0_iff [simp]: - "scale a x = 0 \ a = 0 \ x = 0" -proof cases - assume "a = 0" thus ?thesis by simp +lemma scale_eq_0_iff [simp]: "scale a x = 0 \ a = 0 \ x = 0" +proof (cases "a = 0") + case True + then show ?thesis by simp next - assume anz [simp]: "a \ 0" - { assume "scale a x = 0" - hence "scale (inverse a) (scale a x) = 0" by simp - hence "x = 0" by simp } - thus ?thesis by force + case False + have "x = 0" if "scale a x = 0" + proof - + from False that have "scale (inverse a) (scale a x) = 0" by simp + with False show ?thesis by simp + qed + then show ?thesis by force qed lemma scale_left_imp_eq: - "\a \ 0; scale a x = scale a y\ \ x = y" + assumes nonzero: "a \ 0" + and scale: "scale a x = scale a y" + shows "x = y" proof - - assume nonzero: "a \ 0" - assume "scale a x = scale a y" - hence "scale a (x - y) = 0" + from scale have "scale a (x - y) = 0" by (simp add: scale_right_diff_distrib) - hence "x - y = 0" by (simp add: nonzero) - thus "x = y" by (simp only: right_minus_eq) + with nonzero have "x - y = 0" by simp + then show "x = y" by (simp only: right_minus_eq) qed lemma scale_right_imp_eq: - "\x \ 0; scale a x = scale b x\ \ a = b" + assumes nonzero: "x \ 0" + and scale: "scale a x = scale b x" + shows "a = b" proof - - assume nonzero: "x \ 0" - assume "scale a x = scale b x" - hence "scale (a - b) x = 0" + from scale have "scale (a - b) x = 0" by (simp add: scale_left_diff_distrib) - hence "a - b = 0" by (simp add: nonzero) - thus "a = b" by (simp only: right_minus_eq) + with nonzero have "a - b = 0" by simp + then show "a = b" by (simp only: right_minus_eq) qed -lemma scale_cancel_left [simp]: - "scale a x = scale a y \ x = y \ a = 0" -by (auto intro: scale_left_imp_eq) +lemma scale_cancel_left [simp]: "scale a x = scale a y \ x = y \ a = 0" + by (auto intro: scale_left_imp_eq) -lemma scale_cancel_right [simp]: - "scale a x = scale b x \ a = b \ x = 0" -by (auto intro: scale_right_imp_eq) +lemma scale_cancel_right [simp]: "scale a x = scale b x \ a = b \ x = 0" + by (auto intro: scale_right_imp_eq) end + subsection \Real vector spaces\ class scaleR = fixes scaleR :: "real \ 'a \ 'a" (infixr "*\<^sub>R" 75) begin -abbreviation - divideR :: "'a \ real \ 'a" (infixl "'/\<^sub>R" 70) -where - "x /\<^sub>R r == scaleR (inverse r) x" +abbreviation divideR :: "'a \ real \ 'a" (infixl "'/\<^sub>R" 70) + where "x /\<^sub>R r \ scaleR (inverse r) x" end @@ -150,14 +145,13 @@ and scaleR_scaleR: "scaleR a (scaleR b x) = scaleR (a * b) x" and scaleR_one: "scaleR 1 x = x" -interpretation real_vector: - vector_space "scaleR :: real \ 'a \ 'a::real_vector" -apply unfold_locales -apply (rule scaleR_add_right) -apply (rule scaleR_add_left) -apply (rule scaleR_scaleR) -apply (rule scaleR_one) -done +interpretation real_vector: vector_space "scaleR :: real \ 'a \ 'a::real_vector" + apply unfold_locales + apply (rule scaleR_add_right) + apply (rule scaleR_add_left) + apply (rule scaleR_scaleR) + apply (rule scaleR_one) + done text \Recover original theorem names\ @@ -183,14 +177,13 @@ lemmas scaleR_left_diff_distrib = scaleR_diff_left lemmas scaleR_right_diff_distrib = scaleR_diff_right -lemma scaleR_minus1_left [simp]: - fixes x :: "'a::real_vector" - shows "scaleR (-1) x = - x" +lemma scaleR_minus1_left [simp]: "scaleR (-1) x = - x" + for x :: "'a::real_vector" using scaleR_minus_left [of 1 x] by simp class real_algebra = real_vector + ring + assumes mult_scaleR_left [simp]: "scaleR a x * y = scaleR a (x * y)" - and mult_scaleR_right [simp]: "x * scaleR a y = scaleR a (x * y)" + and mult_scaleR_right [simp]: "x * scaleR a y = scaleR a (x * y)" class real_algebra_1 = real_algebra + ring_1 @@ -201,125 +194,122 @@ instantiation real :: real_field begin -definition - real_scaleR_def [simp]: "scaleR a x = a * x" +definition real_scaleR_def [simp]: "scaleR a x = a * x" -instance proof -qed (simp_all add: algebra_simps) +instance + by standard (simp_all add: algebra_simps) end -interpretation scaleR_left: additive "(\a. scaleR a x::'a::real_vector)" -proof qed (rule scaleR_left_distrib) +interpretation scaleR_left: additive "(\a. scaleR a x :: 'a::real_vector)" + by standard (rule scaleR_left_distrib) -interpretation scaleR_right: additive "(\x. scaleR a x::'a::real_vector)" -proof qed (rule scaleR_right_distrib) +interpretation scaleR_right: additive "(\x. scaleR a x :: 'a::real_vector)" + by standard (rule scaleR_right_distrib) lemma nonzero_inverse_scaleR_distrib: - fixes x :: "'a::real_div_algebra" shows - "\a \ 0; x \ 0\ \ inverse (scaleR a x) = scaleR (inverse a) (inverse x)" -by (rule inverse_unique, simp) + "a \ 0 \ x \ 0 \ inverse (scaleR a x) = scaleR (inverse a) (inverse x)" + for x :: "'a::real_div_algebra" + by (rule inverse_unique) simp -lemma inverse_scaleR_distrib: - fixes x :: "'a::{real_div_algebra, division_ring}" - shows "inverse (scaleR a x) = scaleR (inverse a) (inverse x)" -apply (case_tac "a = 0", simp) -apply (case_tac "x = 0", simp) -apply (erule (1) nonzero_inverse_scaleR_distrib) -done - -lemma setsum_constant_scaleR: - fixes y :: "'a::real_vector" - shows "(\x\A. y) = of_nat (card A) *\<^sub>R y" - apply (cases "finite A") - apply (induct set: finite) - apply (simp_all add: algebra_simps) +lemma inverse_scaleR_distrib: "inverse (scaleR a x) = scaleR (inverse a) (inverse x)" + for x :: "'a::{real_div_algebra,division_ring}" + apply (cases "a = 0") + apply simp + apply (cases "x = 0") + apply simp + apply (erule (1) nonzero_inverse_scaleR_distrib) done -lemma vector_add_divide_simps : - fixes v :: "'a :: real_vector" - shows "v + (b / z) *\<^sub>R w = (if z = 0 then v else (z *\<^sub>R v + b *\<^sub>R w) /\<^sub>R z)" - "a *\<^sub>R v + (b / z) *\<^sub>R w = (if z = 0 then a *\<^sub>R v else ((a * z) *\<^sub>R v + b *\<^sub>R w) /\<^sub>R z)" - "(a / z) *\<^sub>R v + w = (if z = 0 then w else (a *\<^sub>R v + z *\<^sub>R w) /\<^sub>R z)" - "(a / z) *\<^sub>R v + b *\<^sub>R w = (if z = 0 then b *\<^sub>R w else (a *\<^sub>R v + (b * z) *\<^sub>R w) /\<^sub>R z)" - "v - (b / z) *\<^sub>R w = (if z = 0 then v else (z *\<^sub>R v - b *\<^sub>R w) /\<^sub>R z)" - "a *\<^sub>R v - (b / z) *\<^sub>R w = (if z = 0 then a *\<^sub>R v else ((a * z) *\<^sub>R v - b *\<^sub>R w) /\<^sub>R z)" - "(a / z) *\<^sub>R v - w = (if z = 0 then -w else (a *\<^sub>R v - z *\<^sub>R w) /\<^sub>R z)" - "(a / z) *\<^sub>R v - b *\<^sub>R w = (if z = 0 then -b *\<^sub>R w else (a *\<^sub>R v - (b * z) *\<^sub>R w) /\<^sub>R z)" -by (simp_all add: divide_inverse_commute scaleR_add_right real_vector.scale_right_diff_distrib) +lemma setsum_constant_scaleR: "(\x\A. y) = of_nat (card A) *\<^sub>R y" + for y :: "'a::real_vector" + apply (cases "finite A") + apply (induct set: finite) + apply (simp_all add: algebra_simps) + done + +lemma vector_add_divide_simps: + "v + (b / z) *\<^sub>R w = (if z = 0 then v else (z *\<^sub>R v + b *\<^sub>R w) /\<^sub>R z)" + "a *\<^sub>R v + (b / z) *\<^sub>R w = (if z = 0 then a *\<^sub>R v else ((a * z) *\<^sub>R v + b *\<^sub>R w) /\<^sub>R z)" + "(a / z) *\<^sub>R v + w = (if z = 0 then w else (a *\<^sub>R v + z *\<^sub>R w) /\<^sub>R z)" + "(a / z) *\<^sub>R v + b *\<^sub>R w = (if z = 0 then b *\<^sub>R w else (a *\<^sub>R v + (b * z) *\<^sub>R w) /\<^sub>R z)" + "v - (b / z) *\<^sub>R w = (if z = 0 then v else (z *\<^sub>R v - b *\<^sub>R w) /\<^sub>R z)" + "a *\<^sub>R v - (b / z) *\<^sub>R w = (if z = 0 then a *\<^sub>R v else ((a * z) *\<^sub>R v - b *\<^sub>R w) /\<^sub>R z)" + "(a / z) *\<^sub>R v - w = (if z = 0 then -w else (a *\<^sub>R v - z *\<^sub>R w) /\<^sub>R z)" + "(a / z) *\<^sub>R v - b *\<^sub>R w = (if z = 0 then -b *\<^sub>R w else (a *\<^sub>R v - (b * z) *\<^sub>R w) /\<^sub>R z)" + for v :: "'a :: real_vector" + by (simp_all add: divide_inverse_commute scaleR_add_right real_vector.scale_right_diff_distrib) lemma real_vector_affinity_eq: fixes x :: "'a :: real_vector" assumes m0: "m \ 0" shows "m *\<^sub>R x + c = y \ x = inverse m *\<^sub>R y - (inverse m *\<^sub>R c)" + (is "?lhs \ ?rhs") proof - assume h: "m *\<^sub>R x + c = y" - hence "m *\<^sub>R x = y - c" by (simp add: field_simps) - hence "inverse m *\<^sub>R (m *\<^sub>R x) = inverse m *\<^sub>R (y - c)" by simp + assume ?lhs + then have "m *\<^sub>R x = y - c" by (simp add: field_simps) + then have "inverse m *\<^sub>R (m *\<^sub>R x) = inverse m *\<^sub>R (y - c)" by simp then show "x = inverse m *\<^sub>R y - (inverse m *\<^sub>R c)" using m0 by (simp add: real_vector.scale_right_diff_distrib) next - assume h: "x = inverse m *\<^sub>R y - (inverse m *\<^sub>R c)" - show "m *\<^sub>R x + c = y" unfolding h - using m0 by (simp add: real_vector.scale_right_diff_distrib) + assume ?rhs + with m0 show "m *\<^sub>R x + c = y" + by (simp add: real_vector.scale_right_diff_distrib) qed -lemma real_vector_eq_affinity: - fixes x :: "'a :: real_vector" - shows "m \ 0 ==> (y = m *\<^sub>R x + c \ inverse m *\<^sub>R y - (inverse m *\<^sub>R c) = x)" +lemma real_vector_eq_affinity: "m \ 0 \ y = m *\<^sub>R x + c \ inverse m *\<^sub>R y - (inverse m *\<^sub>R c) = x" + for x :: "'a::real_vector" using real_vector_affinity_eq[where m=m and x=x and y=y and c=c] by metis -lemma scaleR_eq_iff [simp]: - fixes a :: "'a :: real_vector" - shows "b + u *\<^sub>R a = a + u *\<^sub>R b \ a=b \ u=1" -proof (cases "u=1") - case True then show ?thesis by auto +lemma scaleR_eq_iff [simp]: "b + u *\<^sub>R a = a + u *\<^sub>R b \ a = b \ u = 1" + for a :: "'a::real_vector" +proof (cases "u = 1") + case True + then show ?thesis by auto next case False - { assume "b + u *\<^sub>R a = a + u *\<^sub>R b" - then have "(u - 1) *\<^sub>R a = (u - 1) *\<^sub>R b" + have "a = b" if "b + u *\<^sub>R a = a + u *\<^sub>R b" + proof - + from that have "(u - 1) *\<^sub>R a = (u - 1) *\<^sub>R b" by (simp add: algebra_simps) - with False have "a=b" + with False show ?thesis by auto - } + qed then show ?thesis by auto qed -lemma scaleR_collapse [simp]: - fixes a :: "'a :: real_vector" - shows "(1 - u) *\<^sub>R a + u *\<^sub>R a = a" -by (simp add: algebra_simps) +lemma scaleR_collapse [simp]: "(1 - u) *\<^sub>R a + u *\<^sub>R a = a" + for a :: "'a::real_vector" + by (simp add: algebra_simps) -subsection \Embedding of the Reals into any \real_algebra_1\: -@{term of_real}\ +subsection \Embedding of the Reals into any \real_algebra_1\: \of_real\\ -definition - of_real :: "real \ 'a::real_algebra_1" where - "of_real r = scaleR r 1" +definition of_real :: "real \ 'a::real_algebra_1" + where "of_real r = scaleR r 1" lemma scaleR_conv_of_real: "scaleR r x = of_real r * x" -by (simp add: of_real_def) + by (simp add: of_real_def) lemma of_real_0 [simp]: "of_real 0 = 0" -by (simp add: of_real_def) + by (simp add: of_real_def) lemma of_real_1 [simp]: "of_real 1 = 1" -by (simp add: of_real_def) + by (simp add: of_real_def) lemma of_real_add [simp]: "of_real (x + y) = of_real x + of_real y" -by (simp add: of_real_def scaleR_left_distrib) + by (simp add: of_real_def scaleR_left_distrib) lemma of_real_minus [simp]: "of_real (- x) = - of_real x" -by (simp add: of_real_def) + by (simp add: of_real_def) lemma of_real_diff [simp]: "of_real (x - y) = of_real x - of_real y" -by (simp add: of_real_def scaleR_left_diff_distrib) + by (simp add: of_real_def scaleR_left_diff_distrib) lemma of_real_mult [simp]: "of_real (x * y) = of_real x * of_real y" -by (simp add: of_real_def mult.commute) + by (simp add: of_real_def mult.commute) lemma of_real_setsum[simp]: "of_real (setsum f s) = (\x\s. of_real (f x))" by (induct s rule: infinite_finite_induct) auto @@ -328,63 +318,56 @@ by (induct s rule: infinite_finite_induct) auto lemma nonzero_of_real_inverse: - "x \ 0 \ of_real (inverse x) = - inverse (of_real x :: 'a::real_div_algebra)" -by (simp add: of_real_def nonzero_inverse_scaleR_distrib) + "x \ 0 \ of_real (inverse x) = inverse (of_real x :: 'a::real_div_algebra)" + by (simp add: of_real_def nonzero_inverse_scaleR_distrib) lemma of_real_inverse [simp]: - "of_real (inverse x) = - inverse (of_real x :: 'a::{real_div_algebra, division_ring})" -by (simp add: of_real_def inverse_scaleR_distrib) + "of_real (inverse x) = inverse (of_real x :: 'a::{real_div_algebra,division_ring})" + by (simp add: of_real_def inverse_scaleR_distrib) lemma nonzero_of_real_divide: - "y \ 0 \ of_real (x / y) = - (of_real x / of_real y :: 'a::real_field)" -by (simp add: divide_inverse nonzero_of_real_inverse) + "y \ 0 \ of_real (x / y) = (of_real x / of_real y :: 'a::real_field)" + by (simp add: divide_inverse nonzero_of_real_inverse) lemma of_real_divide [simp]: "of_real (x / y) = (of_real x / of_real y :: 'a::real_div_algebra)" -by (simp add: divide_inverse) + by (simp add: divide_inverse) lemma of_real_power [simp]: "of_real (x ^ n) = (of_real x :: 'a::{real_algebra_1}) ^ n" -by (induct n) simp_all + by (induct n) simp_all -lemma of_real_eq_iff [simp]: "(of_real x = of_real y) = (x = y)" -by (simp add: of_real_def) +lemma of_real_eq_iff [simp]: "of_real x = of_real y \ x = y" + by (simp add: of_real_def) -lemma inj_of_real: - "inj of_real" +lemma inj_of_real: "inj of_real" by (auto intro: injI) lemmas of_real_eq_0_iff [simp] = of_real_eq_iff [of _ 0, simplified] lemma of_real_eq_id [simp]: "of_real = (id :: real \ real)" -proof - fix r - show "of_real r = id r" - by (simp add: of_real_def) -qed + by (rule ext) (simp add: of_real_def) -text\Collapse nested embeddings\ +text \Collapse nested embeddings.\ lemma of_real_of_nat_eq [simp]: "of_real (of_nat n) = of_nat n" -by (induct n) auto + by (induct n) auto lemma of_real_of_int_eq [simp]: "of_real (of_int z) = of_int z" -by (cases z rule: int_diff_cases, simp) + by (cases z rule: int_diff_cases) simp lemma of_real_numeral [simp]: "of_real (numeral w) = numeral w" -using of_real_of_int_eq [of "numeral w"] by simp + using of_real_of_int_eq [of "numeral w"] by simp lemma of_real_neg_numeral [simp]: "of_real (- numeral w) = - numeral w" -using of_real_of_int_eq [of "- numeral w"] by simp + using of_real_of_int_eq [of "- numeral w"] by simp -text\Every real algebra has characteristic zero\ - +text \Every real algebra has characteristic zero.\ instance real_algebra_1 < ring_char_0 proof - from inj_of_real inj_of_nat have "inj (of_real \ of_nat)" by (rule inj_comp) - then show "inj (of_nat :: nat \ 'a)" by (simp add: comp_def) + from inj_of_real inj_of_nat have "inj (of_real \ of_nat)" + by (rule inj_comp) + then show "inj (of_nat :: nat \ 'a)" + by (simp add: comp_def) qed instance real_field < field_char_0 .. @@ -396,97 +379,91 @@ where "\ = range of_real" lemma Reals_of_real [simp]: "of_real r \ \" -by (simp add: Reals_def) + by (simp add: Reals_def) lemma Reals_of_int [simp]: "of_int z \ \" -by (subst of_real_of_int_eq [symmetric], rule Reals_of_real) + by (subst of_real_of_int_eq [symmetric], rule Reals_of_real) lemma Reals_of_nat [simp]: "of_nat n \ \" -by (subst of_real_of_nat_eq [symmetric], rule Reals_of_real) + by (subst of_real_of_nat_eq [symmetric], rule Reals_of_real) lemma Reals_numeral [simp]: "numeral w \ \" -by (subst of_real_numeral [symmetric], rule Reals_of_real) + by (subst of_real_numeral [symmetric], rule Reals_of_real) lemma Reals_0 [simp]: "0 \ \" -apply (unfold Reals_def) -apply (rule range_eqI) -apply (rule of_real_0 [symmetric]) -done + apply (unfold Reals_def) + apply (rule range_eqI) + apply (rule of_real_0 [symmetric]) + done lemma Reals_1 [simp]: "1 \ \" -apply (unfold Reals_def) -apply (rule range_eqI) -apply (rule of_real_1 [symmetric]) -done + apply (unfold Reals_def) + apply (rule range_eqI) + apply (rule of_real_1 [symmetric]) + done -lemma Reals_add [simp]: "\a \ \; b \ \\ \ a + b \ \" -apply (auto simp add: Reals_def) -apply (rule range_eqI) -apply (rule of_real_add [symmetric]) -done +lemma Reals_add [simp]: "a \ \ \ b \ \ \ a + b \ \" + apply (auto simp add: Reals_def) + apply (rule range_eqI) + apply (rule of_real_add [symmetric]) + done lemma Reals_minus [simp]: "a \ \ \ - a \ \" -apply (auto simp add: Reals_def) -apply (rule range_eqI) -apply (rule of_real_minus [symmetric]) -done + apply (auto simp add: Reals_def) + apply (rule range_eqI) + apply (rule of_real_minus [symmetric]) + done -lemma Reals_diff [simp]: "\a \ \; b \ \\ \ a - b \ \" -apply (auto simp add: Reals_def) -apply (rule range_eqI) -apply (rule of_real_diff [symmetric]) -done +lemma Reals_diff [simp]: "a \ \ \ b \ \ \ a - b \ \" + apply (auto simp add: Reals_def) + apply (rule range_eqI) + apply (rule of_real_diff [symmetric]) + done -lemma Reals_mult [simp]: "\a \ \; b \ \\ \ a * b \ \" -apply (auto simp add: Reals_def) -apply (rule range_eqI) -apply (rule of_real_mult [symmetric]) -done +lemma Reals_mult [simp]: "a \ \ \ b \ \ \ a * b \ \" + apply (auto simp add: Reals_def) + apply (rule range_eqI) + apply (rule of_real_mult [symmetric]) + done -lemma nonzero_Reals_inverse: - fixes a :: "'a::real_div_algebra" - shows "\a \ \; a \ 0\ \ inverse a \ \" -apply (auto simp add: Reals_def) -apply (rule range_eqI) -apply (erule nonzero_of_real_inverse [symmetric]) -done +lemma nonzero_Reals_inverse: "a \ \ \ a \ 0 \ inverse a \ \" + for a :: "'a::real_div_algebra" + apply (auto simp add: Reals_def) + apply (rule range_eqI) + apply (erule nonzero_of_real_inverse [symmetric]) + done -lemma Reals_inverse: - fixes a :: "'a::{real_div_algebra, division_ring}" - shows "a \ \ \ inverse a \ \" -apply (auto simp add: Reals_def) -apply (rule range_eqI) -apply (rule of_real_inverse [symmetric]) -done +lemma Reals_inverse: "a \ \ \ inverse a \ \" + for a :: "'a::{real_div_algebra,division_ring}" + apply (auto simp add: Reals_def) + apply (rule range_eqI) + apply (rule of_real_inverse [symmetric]) + done -lemma Reals_inverse_iff [simp]: - fixes x:: "'a :: {real_div_algebra, division_ring}" - shows "inverse x \ \ \ x \ \" -by (metis Reals_inverse inverse_inverse_eq) +lemma Reals_inverse_iff [simp]: "inverse x \ \ \ x \ \" + for x :: "'a::{real_div_algebra,division_ring}" + by (metis Reals_inverse inverse_inverse_eq) -lemma nonzero_Reals_divide: - fixes a b :: "'a::real_field" - shows "\a \ \; b \ \; b \ 0\ \ a / b \ \" -apply (auto simp add: Reals_def) -apply (rule range_eqI) -apply (erule nonzero_of_real_divide [symmetric]) -done +lemma nonzero_Reals_divide: "a \ \ \ b \ \ \ b \ 0 \ a / b \ \" + for a b :: "'a::real_field" + apply (auto simp add: Reals_def) + apply (rule range_eqI) + apply (erule nonzero_of_real_divide [symmetric]) + done -lemma Reals_divide [simp]: - fixes a b :: "'a::{real_field, field}" - shows "\a \ \; b \ \\ \ a / b \ \" -apply (auto simp add: Reals_def) -apply (rule range_eqI) -apply (rule of_real_divide [symmetric]) -done +lemma Reals_divide [simp]: "a \ \ \ b \ \ \ a / b \ \" + for a b :: "'a::{real_field,field}" + apply (auto simp add: Reals_def) + apply (rule range_eqI) + apply (rule of_real_divide [symmetric]) + done -lemma Reals_power [simp]: - fixes a :: "'a::{real_algebra_1}" - shows "a \ \ \ a ^ n \ \" -apply (auto simp add: Reals_def) -apply (rule range_eqI) -apply (rule of_real_power [symmetric]) -done +lemma Reals_power [simp]: "a \ \ \ a ^ n \ \" + for a :: "'a::real_algebra_1" + apply (auto simp add: Reals_def) + apply (rule range_eqI) + apply (rule of_real_power [symmetric]) + done lemma Reals_cases [cases set: Reals]: assumes "q \ \" @@ -499,49 +476,56 @@ qed lemma setsum_in_Reals [intro,simp]: - assumes "\i. i \ s \ f i \ \" shows "setsum f s \ \" + assumes "\i. i \ s \ f i \ \" + shows "setsum f s \ \" proof (cases "finite s") - case True then show ?thesis using assms - by (induct s rule: finite_induct) auto + case True + then show ?thesis + using assms by (induct s rule: finite_induct) auto next - case False then show ?thesis using assms - by (metis Reals_0 setsum.infinite) + case False + then show ?thesis + using assms by (metis Reals_0 setsum.infinite) qed lemma setprod_in_Reals [intro,simp]: - assumes "\i. i \ s \ f i \ \" shows "setprod f s \ \" + assumes "\i. i \ s \ f i \ \" + shows "setprod f s \ \" proof (cases "finite s") - case True then show ?thesis using assms - by (induct s rule: finite_induct) auto + case True + then show ?thesis + using assms by (induct s rule: finite_induct) auto next - case False then show ?thesis using assms - by (metis Reals_1 setprod.infinite) + case False + then show ?thesis + using assms by (metis Reals_1 setprod.infinite) qed lemma Reals_induct [case_names of_real, induct set: Reals]: "q \ \ \ (\r. P (of_real r)) \ P q" by (rule Reals_cases) auto + subsection \Ordered real vector spaces\ class ordered_real_vector = real_vector + ordered_ab_group_add + assumes scaleR_left_mono: "x \ y \ 0 \ a \ a *\<^sub>R x \ a *\<^sub>R y" - assumes scaleR_right_mono: "a \ b \ 0 \ x \ a *\<^sub>R x \ b *\<^sub>R x" + and scaleR_right_mono: "a \ b \ 0 \ x \ a *\<^sub>R x \ b *\<^sub>R x" begin -lemma scaleR_mono: - "a \ b \ x \ y \ 0 \ b \ 0 \ x \ a *\<^sub>R x \ b *\<^sub>R y" -apply (erule scaleR_right_mono [THEN order_trans], assumption) -apply (erule scaleR_left_mono, assumption) -done +lemma scaleR_mono: "a \ b \ x \ y \ 0 \ b \ 0 \ x \ a *\<^sub>R x \ b *\<^sub>R y" + apply (erule scaleR_right_mono [THEN order_trans]) + apply assumption + apply (erule scaleR_left_mono) + apply assumption + done -lemma scaleR_mono': - "a \ b \ c \ d \ 0 \ a \ 0 \ c \ a *\<^sub>R c \ b *\<^sub>R d" +lemma scaleR_mono': "a \ b \ c \ d \ 0 \ a \ 0 \ c \ a *\<^sub>R c \ b *\<^sub>R d" by (rule scaleR_mono) (auto intro: order.trans) lemma pos_le_divideRI: assumes "0 < c" - assumes "c *\<^sub>R a \ b" + and "c *\<^sub>R a \ b" shows "a \ b /\<^sub>R c" proof - from scaleR_left_mono[OF assms(2)] assms(1) @@ -554,20 +538,22 @@ lemma pos_le_divideR_eq: assumes "0 < c" shows "a \ b /\<^sub>R c \ c *\<^sub>R a \ b" -proof rule - assume "a \ b /\<^sub>R c" - from scaleR_left_mono[OF this] assms - have "c *\<^sub>R a \ c *\<^sub>R (b /\<^sub>R c)" + (is "?lhs \ ?rhs") +proof + assume ?lhs + from scaleR_left_mono[OF this] assms have "c *\<^sub>R a \ c *\<^sub>R (b /\<^sub>R c)" by simp - with assms show "c *\<^sub>R a \ b" + with assms show ?rhs by (simp add: scaleR_one scaleR_scaleR inverse_eq_divide) -qed (rule pos_le_divideRI[OF assms]) +next + assume ?rhs + with assms show ?lhs by (rule pos_le_divideRI) +qed -lemma scaleR_image_atLeastAtMost: - "c > 0 \ scaleR c ` {x..y} = {c *\<^sub>R x..c *\<^sub>R y}" +lemma scaleR_image_atLeastAtMost: "c > 0 \ scaleR c ` {x..y} = {c *\<^sub>R x..c *\<^sub>R y}" apply (auto intro!: scaleR_left_mono) apply (rule_tac x = "inverse c *\<^sub>R xa" in image_eqI) - apply (simp_all add: pos_le_divideR_eq[symmetric] scaleR_scaleR scaleR_one) + apply (simp_all add: pos_le_divideR_eq[symmetric] scaleR_scaleR scaleR_one) done end @@ -576,103 +562,105 @@ fixes a :: "'a :: ordered_real_vector" assumes "c < 0" shows "a \ b /\<^sub>R c \ b \ c *\<^sub>R a" - using pos_le_divideR_eq [of "-c" a "-b"] assms - by simp + using pos_le_divideR_eq [of "-c" a "-b"] assms by simp -lemma scaleR_nonneg_nonneg: "0 \ a \ 0 \ (x::'a::ordered_real_vector) \ 0 \ a *\<^sub>R x" - using scaleR_left_mono [of 0 x a] - by simp +lemma scaleR_nonneg_nonneg: "0 \ a \ 0 \ x \ 0 \ a *\<^sub>R x" + for x :: "'a::ordered_real_vector" + using scaleR_left_mono [of 0 x a] by simp -lemma scaleR_nonneg_nonpos: "0 \ a \ (x::'a::ordered_real_vector) \ 0 \ a *\<^sub>R x \ 0" +lemma scaleR_nonneg_nonpos: "0 \ a \ x \ 0 \ a *\<^sub>R x \ 0" + for x :: "'a::ordered_real_vector" using scaleR_left_mono [of x 0 a] by simp -lemma scaleR_nonpos_nonneg: "a \ 0 \ 0 \ (x::'a::ordered_real_vector) \ a *\<^sub>R x \ 0" +lemma scaleR_nonpos_nonneg: "a \ 0 \ 0 \ x \ a *\<^sub>R x \ 0" + for x :: "'a::ordered_real_vector" using scaleR_right_mono [of a 0 x] by simp -lemma split_scaleR_neg_le: "(0 \ a & x \ 0) | (a \ 0 & 0 \ x) \ - a *\<^sub>R (x::'a::ordered_real_vector) \ 0" +lemma split_scaleR_neg_le: "(0 \ a \ x \ 0) \ (a \ 0 \ 0 \ x) \ a *\<^sub>R x \ 0" + for x :: "'a::ordered_real_vector" by (auto simp add: scaleR_nonneg_nonpos scaleR_nonpos_nonneg) -lemma le_add_iff1: - fixes c d e::"'a::ordered_real_vector" - shows "a *\<^sub>R e + c \ b *\<^sub>R e + d \ (a - b) *\<^sub>R e + c \ d" +lemma le_add_iff1: "a *\<^sub>R e + c \ b *\<^sub>R e + d \ (a - b) *\<^sub>R e + c \ d" + for c d e :: "'a::ordered_real_vector" by (simp add: algebra_simps) -lemma le_add_iff2: - fixes c d e::"'a::ordered_real_vector" - shows "a *\<^sub>R e + c \ b *\<^sub>R e + d \ c \ (b - a) *\<^sub>R e + d" +lemma le_add_iff2: "a *\<^sub>R e + c \ b *\<^sub>R e + d \ c \ (b - a) *\<^sub>R e + d" + for c d e :: "'a::ordered_real_vector" by (simp add: algebra_simps) -lemma scaleR_left_mono_neg: - fixes a b::"'a::ordered_real_vector" - shows "b \ a \ c \ 0 \ c *\<^sub>R a \ c *\<^sub>R b" +lemma scaleR_left_mono_neg: "b \ a \ c \ 0 \ c *\<^sub>R a \ c *\<^sub>R b" + for a b :: "'a::ordered_real_vector" apply (drule scaleR_left_mono [of _ _ "- c"]) - apply simp_all + apply simp_all done -lemma scaleR_right_mono_neg: - fixes c::"'a::ordered_real_vector" - shows "b \ a \ c \ 0 \ a *\<^sub>R c \ b *\<^sub>R c" +lemma scaleR_right_mono_neg: "b \ a \ c \ 0 \ a *\<^sub>R c \ b *\<^sub>R c" + for c :: "'a::ordered_real_vector" apply (drule scaleR_right_mono [of _ _ "- c"]) - apply simp_all + apply simp_all done -lemma scaleR_nonpos_nonpos: "a \ 0 \ (b::'a::ordered_real_vector) \ 0 \ 0 \ a *\<^sub>R b" -using scaleR_right_mono_neg [of a 0 b] by simp +lemma scaleR_nonpos_nonpos: "a \ 0 \ b \ 0 \ 0 \ a *\<^sub>R b" + for b :: "'a::ordered_real_vector" + using scaleR_right_mono_neg [of a 0 b] by simp -lemma split_scaleR_pos_le: - fixes b::"'a::ordered_real_vector" - shows "(0 \ a \ 0 \ b) \ (a \ 0 \ b \ 0) \ 0 \ a *\<^sub>R b" +lemma split_scaleR_pos_le: "(0 \ a \ 0 \ b) \ (a \ 0 \ b \ 0) \ 0 \ a *\<^sub>R b" + for b :: "'a::ordered_real_vector" by (auto simp add: scaleR_nonneg_nonneg scaleR_nonpos_nonpos) lemma zero_le_scaleR_iff: - fixes b::"'a::ordered_real_vector" - shows "0 \ a *\<^sub>R b \ 0 < a \ 0 \ b \ a < 0 \ b \ 0 \ a = 0" (is "?lhs = ?rhs") -proof cases - assume "a \ 0" + fixes b :: "'a::ordered_real_vector" + shows "0 \ a *\<^sub>R b \ 0 < a \ 0 \ b \ a < 0 \ b \ 0 \ a = 0" + (is "?lhs = ?rhs") +proof (cases "a = 0") + case True + then show ?thesis by simp +next + case False show ?thesis proof - assume lhs: ?lhs - { - assume "0 < a" - with lhs have "inverse a *\<^sub>R 0 \ inverse a *\<^sub>R (a *\<^sub>R b)" + assume ?lhs + from \a \ 0\ consider "a > 0" | "a < 0" by arith + then show ?rhs + proof cases + case 1 + with \?lhs\ have "inverse a *\<^sub>R 0 \ inverse a *\<^sub>R (a *\<^sub>R b)" by (intro scaleR_mono) auto - hence ?rhs using \0 < a\ + with 1 show ?thesis by simp - } moreover { - assume "0 > a" - with lhs have "- inverse a *\<^sub>R 0 \ - inverse a *\<^sub>R (a *\<^sub>R b)" + next + case 2 + with \?lhs\ have "- inverse a *\<^sub>R 0 \ - inverse a *\<^sub>R (a *\<^sub>R b)" by (intro scaleR_mono) auto - hence ?rhs using \0 > a\ + with 2 show ?thesis by simp - } ultimately show ?rhs using \a \ 0\ by arith - qed (auto simp: not_le \a \ 0\ intro!: split_scaleR_pos_le) -qed simp + qed + next + assume ?rhs + then show ?lhs + by (auto simp: not_le \a \ 0\ intro!: split_scaleR_pos_le) + qed +qed -lemma scaleR_le_0_iff: - fixes b::"'a::ordered_real_vector" - shows "a *\<^sub>R b \ 0 \ 0 < a \ b \ 0 \ a < 0 \ 0 \ b \ a = 0" +lemma scaleR_le_0_iff: "a *\<^sub>R b \ 0 \ 0 < a \ b \ 0 \ a < 0 \ 0 \ b \ a = 0" + for b::"'a::ordered_real_vector" by (insert zero_le_scaleR_iff [of "-a" b]) force -lemma scaleR_le_cancel_left: - fixes b::"'a::ordered_real_vector" - shows "c *\<^sub>R a \ c *\<^sub>R b \ (0 < c \ a \ b) \ (c < 0 \ b \ a)" +lemma scaleR_le_cancel_left: "c *\<^sub>R a \ c *\<^sub>R b \ (0 < c \ a \ b) \ (c < 0 \ b \ a)" + for b :: "'a::ordered_real_vector" by (auto simp add: neq_iff scaleR_left_mono scaleR_left_mono_neg - dest: scaleR_left_mono[where a="inverse c"] scaleR_left_mono_neg[where c="inverse c"]) + dest: scaleR_left_mono[where a="inverse c"] scaleR_left_mono_neg[where c="inverse c"]) -lemma scaleR_le_cancel_left_pos: - fixes b::"'a::ordered_real_vector" - shows "0 < c \ c *\<^sub>R a \ c *\<^sub>R b \ a \ b" +lemma scaleR_le_cancel_left_pos: "0 < c \ c *\<^sub>R a \ c *\<^sub>R b \ a \ b" + for b :: "'a::ordered_real_vector" by (auto simp: scaleR_le_cancel_left) -lemma scaleR_le_cancel_left_neg: - fixes b::"'a::ordered_real_vector" - shows "c < 0 \ c *\<^sub>R a \ c *\<^sub>R b \ b \ a" +lemma scaleR_le_cancel_left_neg: "c < 0 \ c *\<^sub>R a \ c *\<^sub>R b \ b \ a" + for b :: "'a::ordered_real_vector" by (auto simp: scaleR_le_cancel_left) -lemma scaleR_left_le_one_le: - fixes x::"'a::ordered_real_vector" and a::real - shows "0 \ x \ a \ 1 \ a *\<^sub>R x \ x" +lemma scaleR_left_le_one_le: "0 \ x \ a \ 1 \ a *\<^sub>R x \ x" + for x :: "'a::ordered_real_vector" and a :: real using scaleR_right_mono[of a 1 x] by simp @@ -704,8 +692,8 @@ class real_normed_vector = real_vector + sgn_div_norm + dist_norm + uniformity_dist + open_uniformity + assumes norm_eq_zero [simp]: "norm x = 0 \ x = 0" - and norm_triangle_ineq: "norm (x + y) \ norm x + norm y" - and norm_scaleR [simp]: "norm (scaleR a x) = \a\ * norm x" + and norm_triangle_ineq: "norm (x + y) \ norm x + norm y" + and norm_scaleR [simp]: "norm (scaleR a x) = \a\ * norm x" begin lemma norm_ge_zero [simp]: "0 \ norm x" @@ -724,9 +712,8 @@ class real_normed_algebra_1 = real_algebra_1 + real_normed_algebra + assumes norm_one [simp]: "norm 1 = 1" -lemma (in real_normed_algebra_1) scaleR_power [simp]: - "(scaleR x y) ^ n = scaleR (x^n) (y^n)" - by (induction n) (simp_all add: scaleR_one scaleR_scaleR mult_ac) +lemma (in real_normed_algebra_1) scaleR_power [simp]: "(scaleR x y) ^ n = scaleR (x^n) (y^n)" + by (induct n) (simp_all add: scaleR_one scaleR_scaleR mult_ac) class real_normed_div_algebra = real_div_algebra + real_normed_vector + assumes norm_mult: "norm (x * y) = norm x * norm y" @@ -735,36 +722,31 @@ instance real_normed_div_algebra < real_normed_algebra_1 proof - fix x y :: 'a - show "norm (x * y) \ norm x * norm y" + show "norm (x * y) \ norm x * norm y" for x y :: 'a by (simp add: norm_mult) next have "norm (1 * 1::'a) = norm (1::'a) * norm (1::'a)" by (rule norm_mult) - thus "norm (1::'a) = 1" by simp + then show "norm (1::'a) = 1" by simp qed lemma norm_zero [simp]: "norm (0::'a::real_normed_vector) = 0" -by simp + by simp -lemma zero_less_norm_iff [simp]: - fixes x :: "'a::real_normed_vector" - shows "(0 < norm x) = (x \ 0)" -by (simp add: order_less_le) +lemma zero_less_norm_iff [simp]: "norm x > 0 \ x \ 0" + for x :: "'a::real_normed_vector" + by (simp add: order_less_le) -lemma norm_not_less_zero [simp]: - fixes x :: "'a::real_normed_vector" - shows "\ norm x < 0" -by (simp add: linorder_not_less) +lemma norm_not_less_zero [simp]: "\ norm x < 0" + for x :: "'a::real_normed_vector" + by (simp add: linorder_not_less) -lemma norm_le_zero_iff [simp]: - fixes x :: "'a::real_normed_vector" - shows "(norm x \ 0) = (x = 0)" -by (simp add: order_le_less) +lemma norm_le_zero_iff [simp]: "norm x \ 0 \ x = 0" + for x :: "'a::real_normed_vector" + by (simp add: order_le_less) -lemma norm_minus_cancel [simp]: - fixes x :: "'a::real_normed_vector" - shows "norm (- x) = norm x" +lemma norm_minus_cancel [simp]: "norm (- x) = norm x" + for x :: "'a::real_normed_vector" proof - have "norm (- x) = norm (scaleR (- 1) x)" by (simp only: scaleR_minus_left scaleR_one) @@ -773,78 +755,68 @@ finally show ?thesis by simp qed -lemma norm_minus_commute: - fixes a b :: "'a::real_normed_vector" - shows "norm (a - b) = norm (b - a)" +lemma norm_minus_commute: "norm (a - b) = norm (b - a)" + for a b :: "'a::real_normed_vector" proof - have "norm (- (b - a)) = norm (b - a)" by (rule norm_minus_cancel) - thus ?thesis by simp + then show ?thesis by simp qed - -lemma dist_add_cancel [simp]: - fixes a :: "'a::real_normed_vector" - shows "dist (a + b) (a + c) = dist b c" -by (simp add: dist_norm) + +lemma dist_add_cancel [simp]: "dist (a + b) (a + c) = dist b c" + for a :: "'a::real_normed_vector" + by (simp add: dist_norm) -lemma dist_add_cancel2 [simp]: - fixes a :: "'a::real_normed_vector" - shows "dist (b + a) (c + a) = dist b c" -by (simp add: dist_norm) +lemma dist_add_cancel2 [simp]: "dist (b + a) (c + a) = dist b c" + for a :: "'a::real_normed_vector" + by (simp add: dist_norm) -lemma dist_scaleR [simp]: - fixes a :: "'a::real_normed_vector" - shows "dist (x *\<^sub>R a) (y *\<^sub>R a) = abs (x-y) * norm a" -by (metis dist_norm norm_scaleR scaleR_left.diff) +lemma dist_scaleR [simp]: "dist (x *\<^sub>R a) (y *\<^sub>R a) = \x - y\ * norm a" + for a :: "'a::real_normed_vector" + by (metis dist_norm norm_scaleR scaleR_left.diff) -lemma norm_uminus_minus: "norm (-x - y :: 'a :: real_normed_vector) = norm (x + y)" +lemma norm_uminus_minus: "norm (- x - y :: 'a :: real_normed_vector) = norm (x + y)" by (subst (2) norm_minus_cancel[symmetric], subst minus_add_distrib) simp -lemma norm_triangle_ineq2: - fixes a b :: "'a::real_normed_vector" - shows "norm a - norm b \ norm (a - b)" +lemma norm_triangle_ineq2: "norm a - norm b \ norm (a - b)" + for a b :: "'a::real_normed_vector" proof - have "norm (a - b + b) \ norm (a - b) + norm b" by (rule norm_triangle_ineq) - thus ?thesis by simp + then show ?thesis by simp qed -lemma norm_triangle_ineq3: - fixes a b :: "'a::real_normed_vector" - shows "\norm a - norm b\ \ norm (a - b)" -apply (subst abs_le_iff) -apply auto -apply (rule norm_triangle_ineq2) -apply (subst norm_minus_commute) -apply (rule norm_triangle_ineq2) -done +lemma norm_triangle_ineq3: "\norm a - norm b\ \ norm (a - b)" + for a b :: "'a::real_normed_vector" + apply (subst abs_le_iff) + apply auto + apply (rule norm_triangle_ineq2) + apply (subst norm_minus_commute) + apply (rule norm_triangle_ineq2) + done -lemma norm_triangle_ineq4: - fixes a b :: "'a::real_normed_vector" - shows "norm (a - b) \ norm a + norm b" +lemma norm_triangle_ineq4: "norm (a - b) \ norm a + norm b" + for a b :: "'a::real_normed_vector" proof - have "norm (a + - b) \ norm a + norm (- b)" by (rule norm_triangle_ineq) then show ?thesis by simp qed -lemma norm_diff_ineq: - fixes a b :: "'a::real_normed_vector" - shows "norm a - norm b \ norm (a + b)" +lemma norm_diff_ineq: "norm a - norm b \ norm (a + b)" + for a b :: "'a::real_normed_vector" proof - have "norm a - norm (- b) \ norm (a - - b)" by (rule norm_triangle_ineq2) - thus ?thesis by simp + then show ?thesis by simp qed -lemma norm_add_leD: - fixes a b :: "'a::real_normed_vector" - shows "norm (a + b) \ c \ norm b \ norm a + c" - by (metis add.commute diff_le_eq norm_diff_ineq order.trans) +lemma norm_add_leD: "norm (a + b) \ c \ norm b \ norm a + c" + for a b :: "'a::real_normed_vector" + by (metis add.commute diff_le_eq norm_diff_ineq order.trans) -lemma norm_diff_triangle_ineq: - fixes a b c d :: "'a::real_normed_vector" - shows "norm ((a + b) - (c + d)) \ norm (a - c) + norm (b - d)" +lemma norm_diff_triangle_ineq: "norm ((a + b) - (c + d)) \ norm (a - c) + norm (b - d)" + for a b c d :: "'a::real_normed_vector" proof - have "norm ((a + b) - (c + d)) = norm ((a - c) + (b - d))" by (simp add: algebra_simps) @@ -856,19 +828,19 @@ lemma norm_diff_triangle_le: fixes x y z :: "'a::real_normed_vector" assumes "norm (x - y) \ e1" "norm (y - z) \ e2" - shows "norm (x - z) \ e1 + e2" + shows "norm (x - z) \ e1 + e2" using norm_diff_triangle_ineq [of x y y z] assms by simp lemma norm_diff_triangle_less: fixes x y z :: "'a::real_normed_vector" assumes "norm (x - y) < e1" "norm (y - z) < e2" - shows "norm (x - z) < e1 + e2" + shows "norm (x - z) < e1 + e2" using norm_diff_triangle_ineq [of x y y z] assms by simp lemma norm_triangle_mono: fixes a b :: "'a::real_normed_vector" - shows "\norm a \ r; norm b \ s\ \ norm (a + b) \ r + s" -by (metis add_mono_thms_linordered_semiring(1) norm_triangle_ineq order.trans) + shows "norm a \ r \ norm b \ s \ norm (a + b) \ r + s" + by (metis add_mono_thms_linordered_semiring(1) norm_triangle_ineq order.trans) lemma norm_setsum: fixes f :: "'a \ 'b::real_normed_vector" @@ -881,82 +853,68 @@ shows "norm (setsum f S) \ setsum g S" by (rule order_trans [OF norm_setsum setsum_mono]) (simp add: fg) -lemma abs_norm_cancel [simp]: - fixes a :: "'a::real_normed_vector" - shows "\norm a\ = norm a" -by (rule abs_of_nonneg [OF norm_ge_zero]) +lemma abs_norm_cancel [simp]: "\norm a\ = norm a" + for a :: "'a::real_normed_vector" + by (rule abs_of_nonneg [OF norm_ge_zero]) -lemma norm_add_less: - fixes x y :: "'a::real_normed_vector" - shows "\norm x < r; norm y < s\ \ norm (x + y) < r + s" -by (rule order_le_less_trans [OF norm_triangle_ineq add_strict_mono]) +lemma norm_add_less: "norm x < r \ norm y < s \ norm (x + y) < r + s" + for x y :: "'a::real_normed_vector" + by (rule order_le_less_trans [OF norm_triangle_ineq add_strict_mono]) -lemma norm_mult_less: - fixes x y :: "'a::real_normed_algebra" - shows "\norm x < r; norm y < s\ \ norm (x * y) < r * s" -apply (rule order_le_less_trans [OF norm_mult_ineq]) -apply (simp add: mult_strict_mono') -done +lemma norm_mult_less: "norm x < r \ norm y < s \ norm (x * y) < r * s" + for x y :: "'a::real_normed_algebra" + by (rule order_le_less_trans [OF norm_mult_ineq]) (simp add: mult_strict_mono') -lemma norm_of_real [simp]: - "norm (of_real r :: 'a::real_normed_algebra_1) = \r\" -unfolding of_real_def by simp +lemma norm_of_real [simp]: "norm (of_real r :: 'a::real_normed_algebra_1) = \r\" + by (simp add: of_real_def) -lemma norm_numeral [simp]: - "norm (numeral w::'a::real_normed_algebra_1) = numeral w" -by (subst of_real_numeral [symmetric], subst norm_of_real, simp) +lemma norm_numeral [simp]: "norm (numeral w::'a::real_normed_algebra_1) = numeral w" + by (subst of_real_numeral [symmetric], subst norm_of_real, simp) -lemma norm_neg_numeral [simp]: - "norm (- numeral w::'a::real_normed_algebra_1) = numeral w" -by (subst of_real_neg_numeral [symmetric], subst norm_of_real, simp) +lemma norm_neg_numeral [simp]: "norm (- numeral w::'a::real_normed_algebra_1) = numeral w" + by (subst of_real_neg_numeral [symmetric], subst norm_of_real, simp) -lemma norm_of_real_add1 [simp]: - "norm (of_real x + 1 :: 'a :: real_normed_div_algebra) = abs (x + 1)" +lemma norm_of_real_add1 [simp]: "norm (of_real x + 1 :: 'a :: real_normed_div_algebra) = \x + 1\" by (metis norm_of_real of_real_1 of_real_add) lemma norm_of_real_addn [simp]: - "norm (of_real x + numeral b :: 'a :: real_normed_div_algebra) = abs (x + numeral b)" + "norm (of_real x + numeral b :: 'a :: real_normed_div_algebra) = \x + numeral b\" by (metis norm_of_real of_real_add of_real_numeral) -lemma norm_of_int [simp]: - "norm (of_int z::'a::real_normed_algebra_1) = \of_int z\" -by (subst of_real_of_int_eq [symmetric], rule norm_of_real) +lemma norm_of_int [simp]: "norm (of_int z::'a::real_normed_algebra_1) = \of_int z\" + by (subst of_real_of_int_eq [symmetric], rule norm_of_real) -lemma norm_of_nat [simp]: - "norm (of_nat n::'a::real_normed_algebra_1) = of_nat n" -apply (subst of_real_of_nat_eq [symmetric]) -apply (subst norm_of_real, simp) -done +lemma norm_of_nat [simp]: "norm (of_nat n::'a::real_normed_algebra_1) = of_nat n" + apply (subst of_real_of_nat_eq [symmetric]) + apply (subst norm_of_real, simp) + done -lemma nonzero_norm_inverse: - fixes a :: "'a::real_normed_div_algebra" - shows "a \ 0 \ norm (inverse a) = inverse (norm a)" -apply (rule inverse_unique [symmetric]) -apply (simp add: norm_mult [symmetric]) -done +lemma nonzero_norm_inverse: "a \ 0 \ norm (inverse a) = inverse (norm a)" + for a :: "'a::real_normed_div_algebra" + apply (rule inverse_unique [symmetric]) + apply (simp add: norm_mult [symmetric]) + done -lemma norm_inverse: - fixes a :: "'a::{real_normed_div_algebra, division_ring}" - shows "norm (inverse a) = inverse (norm a)" -apply (case_tac "a = 0", simp) -apply (erule nonzero_norm_inverse) -done +lemma norm_inverse: "norm (inverse a) = inverse (norm a)" + for a :: "'a::{real_normed_div_algebra,division_ring}" + apply (cases "a = 0") + apply simp + apply (erule nonzero_norm_inverse) + done -lemma nonzero_norm_divide: - fixes a b :: "'a::real_normed_field" - shows "b \ 0 \ norm (a / b) = norm a / norm b" -by (simp add: divide_inverse norm_mult nonzero_norm_inverse) +lemma nonzero_norm_divide: "b \ 0 \ norm (a / b) = norm a / norm b" + for a b :: "'a::real_normed_field" + by (simp add: divide_inverse norm_mult nonzero_norm_inverse) -lemma norm_divide: - fixes a b :: "'a::{real_normed_field, field}" - shows "norm (a / b) = norm a / norm b" -by (simp add: divide_inverse norm_mult norm_inverse) +lemma norm_divide: "norm (a / b) = norm a / norm b" + for a b :: "'a::{real_normed_field,field}" + by (simp add: divide_inverse norm_mult norm_inverse) -lemma norm_power_ineq: - fixes x :: "'a::{real_normed_algebra_1}" - shows "norm (x ^ n) \ norm x ^ n" +lemma norm_power_ineq: "norm (x ^ n) \ norm x ^ n" + for x :: "'a::real_normed_algebra_1" proof (induct n) - case 0 show "norm (x ^ 0) \ norm x ^ 0" by simp + case 0 + show "norm (x ^ 0) \ norm x ^ 0" by simp next case (Suc n) have "norm (x * x ^ n) \ norm x * norm (x ^ n)" @@ -967,10 +925,9 @@ by simp qed -lemma norm_power: - fixes x :: "'a::real_normed_div_algebra" - shows "norm (x ^ n) = norm x ^ n" -by (induct n) (simp_all add: norm_mult) +lemma norm_power: "norm (x ^ n) = norm x ^ n" + for x :: "'a::real_normed_div_algebra" + by (induct n) (simp_all add: norm_mult) lemma power_eq_imp_eq_norm: fixes w :: "'a::real_normed_div_algebra" @@ -983,34 +940,31 @@ using assms by (force intro: power_eq_imp_eq_base) qed -lemma norm_mult_numeral1 [simp]: - fixes a b :: "'a::{real_normed_field, field}" - shows "norm (numeral w * a) = numeral w * norm a" -by (simp add: norm_mult) +lemma norm_mult_numeral1 [simp]: "norm (numeral w * a) = numeral w * norm a" + for a b :: "'a::{real_normed_field,field}" + by (simp add: norm_mult) -lemma norm_mult_numeral2 [simp]: - fixes a b :: "'a::{real_normed_field, field}" - shows "norm (a * numeral w) = norm a * numeral w" -by (simp add: norm_mult) +lemma norm_mult_numeral2 [simp]: "norm (a * numeral w) = norm a * numeral w" + for a b :: "'a::{real_normed_field,field}" + by (simp add: norm_mult) -lemma norm_divide_numeral [simp]: - fixes a b :: "'a::{real_normed_field, field}" - shows "norm (a / numeral w) = norm a / numeral w" -by (simp add: norm_divide) +lemma norm_divide_numeral [simp]: "norm (a / numeral w) = norm a / numeral w" + for a b :: "'a::{real_normed_field,field}" + by (simp add: norm_divide) lemma norm_of_real_diff [simp]: - "norm (of_real b - of_real a :: 'a::real_normed_algebra_1) \ \b - a\" + "norm (of_real b - of_real a :: 'a::real_normed_algebra_1) \ \b - a\" by (metis norm_of_real of_real_diff order_refl) -text\Despite a superficial resemblance, \norm_eq_1\ is not relevant.\ +text \Despite a superficial resemblance, \norm_eq_1\ is not relevant.\ lemma square_norm_one: fixes x :: "'a::real_normed_div_algebra" - assumes "x^2 = 1" shows "norm x = 1" + assumes "x\<^sup>2 = 1" + shows "norm x = 1" by (metis assms norm_minus_cancel norm_one power2_eq_1_iff) -lemma norm_less_p1: - fixes x :: "'a::real_normed_algebra_1" - shows "norm x < norm (of_real (norm x) + 1 :: 'a)" +lemma norm_less_p1: "norm x < norm (of_real (norm x) + 1 :: 'a)" + for x :: "'a::real_normed_algebra_1" proof - have "norm x < norm (of_real (norm x + 1) :: 'a)" by (simp add: of_real_def) @@ -1018,14 +972,16 @@ by simp qed -lemma setprod_norm: - fixes f :: "'a \ 'b::{comm_semiring_1,real_normed_div_algebra}" - shows "setprod (\x. norm(f x)) A = norm (setprod f A)" +lemma setprod_norm: "setprod (\x. norm (f x)) A = norm (setprod f A)" + for f :: "'a \ 'b::{comm_semiring_1,real_normed_div_algebra}" by (induct A rule: infinite_finite_induct) (auto simp: norm_mult) lemma norm_setprod_le: - "norm (setprod f A) \ (\a\A. norm (f a :: 'a :: {real_normed_algebra_1, comm_monoid_mult}))" -proof (induction A rule: infinite_finite_induct) + "norm (setprod f A) \ (\a\A. norm (f a :: 'a :: {real_normed_algebra_1,comm_monoid_mult}))" +proof (induct A rule: infinite_finite_induct) + case empty + then show ?case by simp +next case (insert a A) then have "norm (setprod f (insert a A)) \ norm (f a) * norm (setprod f A)" by (simp add: norm_mult_ineq) @@ -1033,13 +989,19 @@ by (rule insert) finally show ?case by (simp add: insert mult_left_mono) -qed simp_all +next + case infinite + then show ?case by simp +qed lemma norm_setprod_diff: fixes z w :: "'i \ 'a::{real_normed_algebra_1, comm_monoid_mult}" shows "(\i. i \ I \ norm (z i) \ 1) \ (\i. i \ I \ norm (w i) \ 1) \ norm ((\i\I. z i) - (\i\I. w i)) \ (\i\I. norm (z i - w i))" proof (induction I rule: infinite_finite_induct) + case empty + then show ?case by simp +next case (insert i I) note insert.hyps[simp] @@ -1047,7 +1009,7 @@ norm ((\i\I. z i) * (z i - w i) + ((\i\I. z i) - (\i\I. w i)) * w i)" (is "_ = norm (?t1 + ?t2)") by (auto simp add: field_simps) - also have "... \ norm ?t1 + norm ?t2" + also have "\ \ norm ?t1 + norm ?t2" by (rule norm_triangle_ineq) also have "norm ?t1 \ norm (\i\I. z i) * norm (z i - w i)" by (rule norm_mult_ineq) @@ -1063,7 +1025,10 @@ using insert by auto finally show ?case by (auto simp add: ac_simps mult_right_mono mult_left_mono) -qed simp_all +next + case infinite + then show ?case by simp +qed lemma norm_power_diff: fixes z w :: "'a::{real_normed_algebra_1, comm_monoid_mult}" @@ -1079,27 +1044,28 @@ finally show ?thesis . qed + subsection \Metric spaces\ class metric_space = uniformity_dist + open_uniformity + assumes dist_eq_0_iff [simp]: "dist x y = 0 \ x = y" - assumes dist_triangle2: "dist x y \ dist x z + dist y z" + and dist_triangle2: "dist x y \ dist x z + dist y z" begin lemma dist_self [simp]: "dist x x = 0" -by simp + by simp lemma zero_le_dist [simp]: "0 \ dist x y" -using dist_triangle2 [of x x y] by simp + using dist_triangle2 [of x x y] by simp lemma zero_less_dist_iff: "0 < dist x y \ x \ y" -by (simp add: less_le) + by (simp add: less_le) lemma dist_not_less_zero [simp]: "\ dist x y < 0" -by (simp add: not_less) + by (simp add: not_less) lemma dist_le_zero_iff [simp]: "dist x y \ 0 \ x = y" -by (simp add: le_less) + by (simp add: le_less) lemma dist_commute: "dist x y = dist y x" proof (rule order_antisym) @@ -1118,56 +1084,52 @@ lemma dist_triangle3: "dist x y \ dist a x + dist a y" using dist_triangle2 [of x y a] by (simp add: dist_commute) -lemma dist_pos_lt: - shows "x \ y ==> 0 < dist x y" -by (simp add: zero_less_dist_iff) +lemma dist_pos_lt: "x \ y \ 0 < dist x y" + by (simp add: zero_less_dist_iff) -lemma dist_nz: - shows "x \ y \ 0 < dist x y" -by (simp add: zero_less_dist_iff) +lemma dist_nz: "x \ y \ 0 < dist x y" + by (simp add: zero_less_dist_iff) declare dist_nz [symmetric, simp] -lemma dist_triangle_le: - shows "dist x z + dist y z <= e \ dist x y <= e" -by (rule order_trans [OF dist_triangle2]) +lemma dist_triangle_le: "dist x z + dist y z \ e \ dist x y \ e" + by (rule order_trans [OF dist_triangle2]) -lemma dist_triangle_lt: - shows "dist x z + dist y z < e ==> dist x y < e" -by (rule le_less_trans [OF dist_triangle2]) +lemma dist_triangle_lt: "dist x z + dist y z < e \ dist x y < e" + by (rule le_less_trans [OF dist_triangle2]) -lemma dist_triangle_less_add: - "\dist x1 y < e1; dist x2 y < e2\ \ dist x1 x2 < e1 + e2" -by (rule dist_triangle_lt [where z=y], simp) +lemma dist_triangle_less_add: "dist x1 y < e1 \ dist x2 y < e2 \ dist x1 x2 < e1 + e2" + by (rule dist_triangle_lt [where z=y]) simp -lemma dist_triangle_half_l: - shows "dist x1 y < e / 2 \ dist x2 y < e / 2 \ dist x1 x2 < e" -by (rule dist_triangle_lt [where z=y], simp) +lemma dist_triangle_half_l: "dist x1 y < e / 2 \ dist x2 y < e / 2 \ dist x1 x2 < e" + by (rule dist_triangle_lt [where z=y]) simp -lemma dist_triangle_half_r: - shows "dist y x1 < e / 2 \ dist y x2 < e / 2 \ dist x1 x2 < e" -by (rule dist_triangle_half_l, simp_all add: dist_commute) +lemma dist_triangle_half_r: "dist y x1 < e / 2 \ dist y x2 < e / 2 \ dist x1 x2 < e" + by (rule dist_triangle_half_l) (simp_all add: dist_commute) subclass uniform_space proof - fix E x assume "eventually E uniformity" + fix E x + assume "eventually E uniformity" then obtain e where E: "0 < e" "\x y. dist x y < e \ E (x, y)" - unfolding eventually_uniformity_metric by auto + by (auto simp: eventually_uniformity_metric) then show "E (x, x)" "\\<^sub>F (x, y) in uniformity. E (y, x)" - unfolding eventually_uniformity_metric by (auto simp: dist_commute) - + by (auto simp: eventually_uniformity_metric dist_commute) show "\D. eventually D uniformity \ (\x y z. D (x, y) \ D (y, z) \ E (x, z))" - using E dist_triangle_half_l[where e=e] unfolding eventually_uniformity_metric + using E dist_triangle_half_l[where e=e] + unfolding eventually_uniformity_metric by (intro exI[of _ "\(x, y). dist x y < e / 2"] exI[of _ "e/2"] conjI) - (auto simp: dist_commute) + (auto simp: dist_commute) qed lemma open_dist: "open S \ (\x\S. \e>0. \y. dist y x < e \ y \ S)" - unfolding open_uniformity eventually_uniformity_metric by (simp add: dist_commute) + by (simp add: dist_commute open_uniformity eventually_uniformity_metric) lemma open_ball: "open {y. dist x y < d}" -proof (unfold open_dist, intro ballI) - fix y assume *: "y \ {y. dist x y < d}" + unfolding open_dist +proof (intro ballI) + fix y + assume *: "y \ {y. dist x y < d}" then show "\e>0. \z. dist z y < e \ z \ {y. dist x y < d}" by (auto intro!: exI[of _ "d - dist x y"] simp: field_simps dist_triangle_lt) qed @@ -1177,7 +1139,8 @@ fix x show "\A::nat \ 'a set. (\i. x \ A i \ open (A i)) \ (\S. open S \ x \ S \ (\i. A i \ S))" proof (safe intro!: exI[of _ "\n. {y. dist x y < inverse (Suc n)}"]) - fix S assume "open S" "x \ S" + fix S + assume "open S" "x \ S" then obtain e where e: "0 < e" and "{y. dist x y < e} \ S" by (auto simp: open_dist subset_eq dist_commute) moreover @@ -1198,34 +1161,33 @@ assume xy: "x \ y" let ?U = "{y'. dist x y' < dist x y / 2}" let ?V = "{x'. dist y x' < dist x y / 2}" - have th0: "\d x y z. (d x z :: real) \ d x y + d y z \ d y z = d z y - \ \(d x y * 2 < d x z \ d z y * 2 < d x z)" by arith + have *: "d x z \ d x y + d y z \ d y z = d z y \ \ (d x y * 2 < d x z \ d z y * 2 < d x z)" + for d :: "'a \ 'a \ real" and x y z :: 'a + by arith have "open ?U \ open ?V \ x \ ?U \ y \ ?V \ ?U \ ?V = {}" - using dist_pos_lt[OF xy] th0[of dist, OF dist_triangle dist_commute] + using dist_pos_lt[OF xy] *[of dist, OF dist_triangle dist_commute] using open_ball[of _ "dist x y / 2"] by auto then show "\U V. open U \ open V \ x \ U \ y \ V \ U \ V = {}" by blast qed text \Every normed vector space is a metric space.\ - instance real_normed_vector < metric_space proof - fix x y :: 'a show "dist x y = 0 \ x = y" - unfolding dist_norm by simp -next - fix x y z :: 'a show "dist x y \ dist x z + dist y z" - unfolding dist_norm - using norm_triangle_ineq4 [of "x - z" "y - z"] by simp + fix x y z :: 'a + show "dist x y = 0 \ x = y" + by (simp add: dist_norm) + show "dist x y \ dist x z + dist y z" + using norm_triangle_ineq4 [of "x - z" "y - z"] by (simp add: dist_norm) qed + subsection \Class instances for real numbers\ instantiation real :: real_normed_field begin -definition dist_real_def: - "dist x y = \x - y\" +definition dist_real_def: "dist x y = \x - y\" definition uniformity_real_def [code del]: "(uniformity :: (real \ real) filter) = (INF e:{0 <..}. principal {(x, y). dist x y < e})" @@ -1233,29 +1195,28 @@ definition open_real_def [code del]: "open (U :: real set) \ (\x\U. eventually (\(x', y). x' = x \ y \ U) uniformity)" -definition real_norm_def [simp]: - "norm r = \r\" +definition real_norm_def [simp]: "norm r = \r\" instance -apply (intro_classes, unfold real_norm_def real_scaleR_def) -apply (rule dist_real_def) -apply (simp add: sgn_real_def) -apply (rule uniformity_real_def) -apply (rule open_real_def) -apply (rule abs_eq_0) -apply (rule abs_triangle_ineq) -apply (rule abs_mult) -apply (rule abs_mult) -done + apply intro_classes + apply (unfold real_norm_def real_scaleR_def) + apply (rule dist_real_def) + apply (simp add: sgn_real_def) + apply (rule uniformity_real_def) + apply (rule open_real_def) + apply (rule abs_eq_0) + apply (rule abs_triangle_ineq) + apply (rule abs_mult) + apply (rule abs_mult) + done end declare uniformity_Abort[where 'a=real, code] -lemma dist_of_real [simp]: - fixes a :: "'a::real_normed_div_algebra" - shows "dist (of_real x :: 'a) (of_real y) = dist x y" -by (metis dist_norm norm_of_real of_real_diff real_norm_def) +lemma dist_of_real [simp]: "dist (of_real x :: 'a) (of_real y) = dist x y" + for a :: "'a::real_normed_div_algebra" + by (metis dist_norm norm_of_real of_real_diff real_norm_def) declare [[code abort: "open :: real set \ bool"]] @@ -1263,7 +1224,8 @@ proof show "(open :: real set \ bool) = generate_topology (range lessThan \ range greaterThan)" proof (rule ext, safe) - fix S :: "real set" assume "open S" + fix S :: "real set" + assume "open S" then obtain f where "\x\S. 0 < f x \ (\y. dist y x < f x \ y \ S)" unfolding open_dist bchoice_iff .. then have *: "S = (\x\S. {x - f x <..} \ {..< x + f x})" @@ -1271,23 +1233,26 @@ show "generate_topology (range lessThan \ range greaterThan) S" apply (subst *) apply (intro generate_topology_Union generate_topology.Int) - apply (auto intro: generate_topology.Basis) + apply (auto intro: generate_topology.Basis) done next - fix S :: "real set" assume "generate_topology (range lessThan \ range greaterThan) S" + fix S :: "real set" + assume "generate_topology (range lessThan \ range greaterThan) S" moreover have "\a::real. open {.. (\y. \y - x\ < a - x \ y \ {..e>0. \y. \y - x\ < e \ y \ {.. (\y. \y - x\ < a - x \ y \ {..e>0. \y. \y - x\ < e \ y \ {..a::real. open {a <..}" unfolding open_dist dist_real_def proof clarify - fix x a :: real assume "a < x" - hence "0 < x - a \ (\y. \y - x\ < x - a \ y \ {a<..})" by auto - thus "\e>0. \y. \y - x\ < e \ y \ {a<..}" .. + fix x a :: real + assume "a < x" + then have "0 < x - a \ (\y. \y - x\ < x - a \ y \ {a<..})" by auto + then show "\e>0. \y. \y - x\ < e \ y \ {a<..}" .. qed ultimately show "open S" by induct auto @@ -1303,66 +1268,67 @@ lemmas closed_real_atLeast = closed_atLeast[where 'a=real] lemmas closed_real_atLeastAtMost = closed_atLeastAtMost[where 'a=real] + subsection \Extra type constraints\ text \Only allow @{term "open"} in class \topological_space\.\ - setup \Sign.add_const_constraint (@{const_name "open"}, SOME @{typ "'a::topological_space set \ bool"})\ text \Only allow @{term "uniformity"} in class \uniform_space\.\ - setup \Sign.add_const_constraint (@{const_name "uniformity"}, SOME @{typ "('a::uniformity \ 'a) filter"})\ text \Only allow @{term dist} in class \metric_space\.\ - setup \Sign.add_const_constraint (@{const_name dist}, SOME @{typ "'a::metric_space \ 'a \ real"})\ text \Only allow @{term norm} in class \real_normed_vector\.\ - setup \Sign.add_const_constraint (@{const_name norm}, SOME @{typ "'a::real_normed_vector \ real"})\ + subsection \Sign function\ -lemma norm_sgn: - "norm (sgn(x::'a::real_normed_vector)) = (if x = 0 then 0 else 1)" -by (simp add: sgn_div_norm) +lemma norm_sgn: "norm (sgn x) = (if x = 0 then 0 else 1)" + for x :: "'a::real_normed_vector" + by (simp add: sgn_div_norm) -lemma sgn_zero [simp]: "sgn(0::'a::real_normed_vector) = 0" -by (simp add: sgn_div_norm) +lemma sgn_zero [simp]: "sgn (0::'a::real_normed_vector) = 0" + by (simp add: sgn_div_norm) -lemma sgn_zero_iff: "(sgn(x::'a::real_normed_vector) = 0) = (x = 0)" -by (simp add: sgn_div_norm) +lemma sgn_zero_iff: "sgn x = 0 \ x = 0" + for x :: "'a::real_normed_vector" + by (simp add: sgn_div_norm) -lemma sgn_minus: "sgn (- x) = - sgn(x::'a::real_normed_vector)" -by (simp add: sgn_div_norm) +lemma sgn_minus: "sgn (- x) = - sgn x" + for x :: "'a::real_normed_vector" + by (simp add: sgn_div_norm) -lemma sgn_scaleR: - "sgn (scaleR r x) = scaleR (sgn r) (sgn(x::'a::real_normed_vector))" -by (simp add: sgn_div_norm ac_simps) +lemma sgn_scaleR: "sgn (scaleR r x) = scaleR (sgn r) (sgn x)" + for x :: "'a::real_normed_vector" + by (simp add: sgn_div_norm ac_simps) lemma sgn_one [simp]: "sgn (1::'a::real_normed_algebra_1) = 1" -by (simp add: sgn_div_norm) + by (simp add: sgn_div_norm) -lemma sgn_of_real: - "sgn (of_real r::'a::real_normed_algebra_1) = of_real (sgn r)" -unfolding of_real_def by (simp only: sgn_scaleR sgn_one) +lemma sgn_of_real: "sgn (of_real r :: 'a::real_normed_algebra_1) = of_real (sgn r)" + unfolding of_real_def by (simp only: sgn_scaleR sgn_one) -lemma sgn_mult: - fixes x y :: "'a::real_normed_div_algebra" - shows "sgn (x * y) = sgn x * sgn y" -by (simp add: sgn_div_norm norm_mult mult.commute) +lemma sgn_mult: "sgn (x * y) = sgn x * sgn y" + for x y :: "'a::real_normed_div_algebra" + by (simp add: sgn_div_norm norm_mult mult.commute) -lemma real_sgn_eq: "sgn (x::real) = x / \x\" +lemma real_sgn_eq: "sgn x = x / \x\" + for x :: real by (simp add: sgn_div_norm divide_inverse) -lemma zero_le_sgn_iff [simp]: "0 \ sgn x \ 0 \ (x::real)" +lemma zero_le_sgn_iff [simp]: "0 \ sgn x \ 0 \ x" + for x :: real by (cases "0::real" x rule: linorder_cases) simp_all -lemma sgn_le_0_iff [simp]: "sgn x \ 0 \ (x::real) \ 0" +lemma sgn_le_0_iff [simp]: "sgn x \ 0 \ x \ 0" + for x :: real by (cases "0::real" x rule: linorder_cases) simp_all lemma norm_conv_dist: "norm x = dist x 0" @@ -1370,10 +1336,9 @@ declare norm_conv_dist [symmetric, simp] -lemma dist_0_norm [simp]: - fixes x :: "'a::real_normed_vector" - shows "dist 0 x = norm x" -unfolding dist_norm by simp +lemma dist_0_norm [simp]: "dist 0 x = norm x" + for x :: "'a::real_normed_vector" + by (simp add: dist_norm) lemma dist_diff [simp]: "dist a (a - b) = norm b" "dist (a - b) a = norm b" by (simp_all add: dist_norm) @@ -1390,23 +1355,25 @@ "dist (of_nat m) (of_nat n :: 'a :: real_normed_algebra_1) = of_int \int m - int n\" by (subst (1 2) of_int_of_nat_eq [symmetric]) (rule dist_of_int) + subsection \Bounded Linear and Bilinear Operators\ locale linear = additive f for f :: "'a::real_vector \ 'b::real_vector" + assumes scaleR: "f (scaleR r x) = scaleR r (f x)" lemma linear_imp_scaleR: - assumes "linear D" obtains d where "D = (\x. x *\<^sub>R d)" + assumes "linear D" + obtains d where "D = (\x. x *\<^sub>R d)" by (metis assms linear.scaleR mult.commute mult.left_neutral real_scaleR_def) corollary real_linearD: fixes f :: "real \ real" assumes "linear f" obtains c where "f = op* c" -by (rule linear_imp_scaleR [OF assms]) (force simp: scaleR_conv_of_real) + by (rule linear_imp_scaleR [OF assms]) (force simp: scaleR_conv_of_real) lemma linearI: assumes "\x y. f (x + y) = f x + f y" - assumes "\c x. f (c *\<^sub>R x) = c *\<^sub>R f x" + and "\c x. f (c *\<^sub>R x) = c *\<^sub>R f x" shows "linear f" by standard (rule assms)+ @@ -1414,8 +1381,7 @@ assumes bounded: "\K. \x. norm (f x) \ norm x * K" begin -lemma pos_bounded: - "\K>0. \x. norm (f x) \ norm x * K" +lemma pos_bounded: "\K>0. \x. norm (f x) \ norm x * K" proof - obtain K where K: "\x. norm (f x) \ norm x * K" using bounded by blast @@ -1432,118 +1398,107 @@ qed qed -lemma nonneg_bounded: - "\K\0. \x. norm (f x) \ norm x * K" -proof - - from pos_bounded - show ?thesis by (auto intro: order_less_imp_le) -qed +lemma nonneg_bounded: "\K\0. \x. norm (f x) \ norm x * K" + using pos_bounded by (auto intro: order_less_imp_le) -lemma linear: "linear f" +lemma linear: "linear f" by (fact local.linear_axioms) end lemma bounded_linear_intro: assumes "\x y. f (x + y) = f x + f y" - assumes "\r x. f (scaleR r x) = scaleR r (f x)" - assumes "\x. norm (f x) \ norm x * K" + and "\r x. f (scaleR r x) = scaleR r (f x)" + and "\x. norm (f x) \ norm x * K" shows "bounded_linear f" by standard (blast intro: assms)+ locale bounded_bilinear = - fixes prod :: "['a::real_normed_vector, 'b::real_normed_vector] - \ 'c::real_normed_vector" + fixes prod :: "'a::real_normed_vector \ 'b::real_normed_vector \ 'c::real_normed_vector" (infixl "**" 70) assumes add_left: "prod (a + a') b = prod a b + prod a' b" - assumes add_right: "prod a (b + b') = prod a b + prod a b'" - assumes scaleR_left: "prod (scaleR r a) b = scaleR r (prod a b)" - assumes scaleR_right: "prod a (scaleR r b) = scaleR r (prod a b)" - assumes bounded: "\K. \a b. norm (prod a b) \ norm a * norm b * K" + and add_right: "prod a (b + b') = prod a b + prod a b'" + and scaleR_left: "prod (scaleR r a) b = scaleR r (prod a b)" + and scaleR_right: "prod a (scaleR r b) = scaleR r (prod a b)" + and bounded: "\K. \a b. norm (prod a b) \ norm a * norm b * K" begin -lemma pos_bounded: - "\K>0. \a b. norm (a ** b) \ norm a * norm b * K" -apply (cut_tac bounded, erule exE) -apply (rule_tac x="max 1 K" in exI, safe) -apply (rule order_less_le_trans [OF zero_less_one max.cobounded1]) -apply (drule spec, drule spec, erule order_trans) -apply (rule mult_left_mono [OF max.cobounded2]) -apply (intro mult_nonneg_nonneg norm_ge_zero) -done +lemma pos_bounded: "\K>0. \a b. norm (a ** b) \ norm a * norm b * K" + apply (insert bounded) + apply (erule exE) + apply (rule_tac x="max 1 K" in exI) + apply safe + apply (rule order_less_le_trans [OF zero_less_one max.cobounded1]) + apply (drule spec) + apply (drule spec) + apply (erule order_trans) + apply (rule mult_left_mono [OF max.cobounded2]) + apply (intro mult_nonneg_nonneg norm_ge_zero) + done -lemma nonneg_bounded: - "\K\0. \a b. norm (a ** b) \ norm a * norm b * K" -proof - - from pos_bounded - show ?thesis by (auto intro: order_less_imp_le) -qed +lemma nonneg_bounded: "\K\0. \a b. norm (a ** b) \ norm a * norm b * K" + using pos_bounded by (auto intro: order_less_imp_le) lemma additive_right: "additive (\b. prod a b)" -by (rule additive.intro, rule add_right) + by (rule additive.intro, rule add_right) lemma additive_left: "additive (\a. prod a b)" -by (rule additive.intro, rule add_left) + by (rule additive.intro, rule add_left) lemma zero_left: "prod 0 b = 0" -by (rule additive.zero [OF additive_left]) + by (rule additive.zero [OF additive_left]) lemma zero_right: "prod a 0 = 0" -by (rule additive.zero [OF additive_right]) + by (rule additive.zero [OF additive_right]) lemma minus_left: "prod (- a) b = - prod a b" -by (rule additive.minus [OF additive_left]) + by (rule additive.minus [OF additive_left]) lemma minus_right: "prod a (- b) = - prod a b" -by (rule additive.minus [OF additive_right]) + by (rule additive.minus [OF additive_right]) -lemma diff_left: - "prod (a - a') b = prod a b - prod a' b" -by (rule additive.diff [OF additive_left]) +lemma diff_left: "prod (a - a') b = prod a b - prod a' b" + by (rule additive.diff [OF additive_left]) -lemma diff_right: - "prod a (b - b') = prod a b - prod a b'" -by (rule additive.diff [OF additive_right]) +lemma diff_right: "prod a (b - b') = prod a b - prod a b'" + by (rule additive.diff [OF additive_right]) -lemma setsum_left: - "prod (setsum g S) x = setsum ((\i. prod (g i) x)) S" -by (rule additive.setsum [OF additive_left]) +lemma setsum_left: "prod (setsum g S) x = setsum ((\i. prod (g i) x)) S" + by (rule additive.setsum [OF additive_left]) -lemma setsum_right: - "prod x (setsum g S) = setsum ((\i. (prod x (g i)))) S" -by (rule additive.setsum [OF additive_right]) +lemma setsum_right: "prod x (setsum g S) = setsum ((\i. (prod x (g i)))) S" + by (rule additive.setsum [OF additive_right]) -lemma bounded_linear_left: - "bounded_linear (\a. a ** b)" -apply (cut_tac bounded, safe) -apply (rule_tac K="norm b * K" in bounded_linear_intro) -apply (rule add_left) -apply (rule scaleR_left) -apply (simp add: ac_simps) -done +lemma bounded_linear_left: "bounded_linear (\a. a ** b)" + apply (insert bounded) + apply safe + apply (rule_tac K="norm b * K" in bounded_linear_intro) + apply (rule add_left) + apply (rule scaleR_left) + apply (simp add: ac_simps) + done -lemma bounded_linear_right: - "bounded_linear (\b. a ** b)" -apply (cut_tac bounded, safe) -apply (rule_tac K="norm a * K" in bounded_linear_intro) -apply (rule add_right) -apply (rule scaleR_right) -apply (simp add: ac_simps) -done +lemma bounded_linear_right: "bounded_linear (\b. a ** b)" + apply (insert bounded) + apply safe + apply (rule_tac K="norm a * K" in bounded_linear_intro) + apply (rule add_right) + apply (rule scaleR_right) + apply (simp add: ac_simps) + done -lemma prod_diff_prod: - "(x ** y - a ** b) = (x - a) ** (y - b) + (x - a) ** b + a ** (y - b)" -by (simp add: diff_left diff_right) +lemma prod_diff_prod: "(x ** y - a ** b) = (x - a) ** (y - b) + (x - a) ** b + a ** (y - b)" + by (simp add: diff_left diff_right) lemma flip: "bounded_bilinear (\x y. y ** x)" apply standard - apply (rule add_right) - apply (rule add_left) - apply (rule scaleR_right) - apply (rule scaleR_left) + apply (rule add_right) + apply (rule add_left) + apply (rule scaleR_right) + apply (rule scaleR_left) apply (subst mult.commute) - using bounded + apply (insert bounded) apply blast done @@ -1557,11 +1512,10 @@ "\r a b. g (r *\<^sub>R a) ** b = r *\<^sub>R (g a ** b)" "\a r b. g a ** (r *\<^sub>R b) = r *\<^sub>R (g a ** b)" by (auto simp: g.add add_left add_right g.scaleR scaleR_left scaleR_right) - from g.nonneg_bounded nonneg_bounded - obtain K L - where nn: "0 \ K" "0 \ L" - and K: "\x. norm (g x) \ norm x * K" - and L: "\a b. norm (a ** b) \ norm a * norm b * L" + from g.nonneg_bounded nonneg_bounded obtain K L + where nn: "0 \ K" "0 \ L" + and K: "\x. norm (g x) \ norm x * K" + and L: "\a b. norm (a ** b) \ norm a * norm b * L" by auto have "norm (g a ** b) \ norm a * K * norm b * L" for a b by (auto intro!: order_trans[OF K] order_trans[OF L] mult_mono simp: nn) @@ -1569,8 +1523,7 @@ by (auto intro!: exI[where x="K * L"] simp: ac_simps) qed -lemma comp: - "bounded_linear f \ bounded_linear g \ bounded_bilinear (\x y. f x ** g y)" +lemma comp: "bounded_linear f \ bounded_linear g \ bounded_bilinear (\x y. f x ** g y)" by (rule bounded_bilinear.flip[OF bounded_bilinear.comp1[OF bounded_bilinear.flip[OF comp1]]]) end @@ -1583,15 +1536,17 @@ lemma bounded_linear_add: assumes "bounded_linear f" - assumes "bounded_linear g" + and "bounded_linear g" shows "bounded_linear (\x. f x + g x)" proof - interpret f: bounded_linear f by fact interpret g: bounded_linear g by fact show ?thesis proof - from f.bounded obtain Kf where Kf: "\x. norm (f x) \ norm x * Kf" by blast - from g.bounded obtain Kg where Kg: "\x. norm (g x) \ norm x * Kg" by blast + from f.bounded obtain Kf where Kf: "norm (f x) \ norm x * Kf" for x + by blast + from g.bounded obtain Kg where Kg: "norm (g x) \ norm x * Kg" for x + by blast show "\K. \x. norm (f x + g x) \ norm x * K" using add_mono[OF Kf Kg] by (intro exI[of _ "Kf + Kg"]) (auto simp: field_simps intro: norm_triangle_ineq order_trans) @@ -1603,9 +1558,10 @@ shows "bounded_linear (\x. - f x)" proof - interpret f: bounded_linear f by fact - show ?thesis apply (unfold_locales) - apply (simp add: f.add) - apply (simp add: f.scaleR) + show ?thesis + apply unfold_locales + apply (simp add: f.add) + apply (simp add: f.scaleR) apply (simp add: f.bounded) done qed @@ -1618,31 +1574,32 @@ fixes f :: "'i \ 'a::real_normed_vector \ 'b::real_normed_vector" assumes "\i. i \ I \ bounded_linear (f i)" shows "bounded_linear (\x. \i\I. f i x)" -proof cases - assume "finite I" - from this show ?thesis - using assms - by (induct I) (auto intro!: bounded_linear_add) -qed simp +proof (cases "finite I") + case True + then show ?thesis + using assms by induct (auto intro!: bounded_linear_add) +next + case False + then show ?thesis by simp +qed lemma bounded_linear_compose: assumes "bounded_linear f" - assumes "bounded_linear g" + and "bounded_linear g" shows "bounded_linear (\x. f (g x))" proof - interpret f: bounded_linear f by fact interpret g: bounded_linear g by fact - show ?thesis proof (unfold_locales) - fix x y show "f (g (x + y)) = f (g x) + f (g y)" + show ?thesis + proof unfold_locales + show "f (g (x + y)) = f (g x) + f (g y)" for x y by (simp only: f.add g.add) - next - fix r x show "f (g (scaleR r x)) = scaleR r (f (g x))" + show "f (g (scaleR r x)) = scaleR r (f (g x))" for r x by (simp only: f.scaleR g.scaleR) - next - from f.pos_bounded - obtain Kf where f: "\x. norm (f x) \ norm x * Kf" and Kf: "0 < Kf" by blast - from g.pos_bounded - obtain Kg where g: "\x. norm (g x) \ norm x * Kg" by blast + from f.pos_bounded obtain Kf where f: "\x. norm (f x) \ norm x * Kf" and Kf: "0 < Kf" + by blast + from g.pos_bounded obtain Kg where g: "\x. norm (g x) \ norm x * Kg" + by blast show "\K. \x. norm (f (g x)) \ norm x * K" proof (intro exI allI) fix x @@ -1657,24 +1614,21 @@ qed qed -lemma bounded_bilinear_mult: - "bounded_bilinear (op * :: 'a \ 'a \ 'a::real_normed_algebra)" -apply (rule bounded_bilinear.intro) -apply (rule distrib_right) -apply (rule distrib_left) -apply (rule mult_scaleR_left) -apply (rule mult_scaleR_right) -apply (rule_tac x="1" in exI) -apply (simp add: norm_mult_ineq) -done +lemma bounded_bilinear_mult: "bounded_bilinear (op * :: 'a \ 'a \ 'a::real_normed_algebra)" + apply (rule bounded_bilinear.intro) + apply (rule distrib_right) + apply (rule distrib_left) + apply (rule mult_scaleR_left) + apply (rule mult_scaleR_right) + apply (rule_tac x="1" in exI) + apply (simp add: norm_mult_ineq) + done -lemma bounded_linear_mult_left: - "bounded_linear (\x::'a::real_normed_algebra. x * y)" +lemma bounded_linear_mult_left: "bounded_linear (\x::'a::real_normed_algebra. x * y)" using bounded_bilinear_mult by (rule bounded_bilinear.bounded_linear_left) -lemma bounded_linear_mult_right: - "bounded_linear (\y::'a::real_normed_algebra. x * y)" +lemma bounded_linear_mult_right: "bounded_linear (\y::'a::real_normed_algebra. x * y)" using bounded_bilinear_mult by (rule bounded_bilinear.bounded_linear_right) @@ -1684,18 +1638,19 @@ lemmas bounded_linear_const_mult = bounded_linear_mult_right [THEN bounded_linear_compose] -lemma bounded_linear_divide: - "bounded_linear (\x::'a::real_normed_field. x / y)" +lemma bounded_linear_divide: "bounded_linear (\x. x / y)" + for y :: "'a::real_normed_field" unfolding divide_inverse by (rule bounded_linear_mult_left) lemma bounded_bilinear_scaleR: "bounded_bilinear scaleR" -apply (rule bounded_bilinear.intro) -apply (rule scaleR_left_distrib) -apply (rule scaleR_right_distrib) -apply simp -apply (rule scaleR_left_commute) -apply (rule_tac x="1" in exI, simp) -done + apply (rule bounded_bilinear.intro) + apply (rule scaleR_left_distrib) + apply (rule scaleR_right_distrib) + apply simp + apply (rule scaleR_left_commute) + apply (rule_tac x="1" in exI) + apply simp + done lemma bounded_linear_scaleR_left: "bounded_linear (\r. scaleR r x)" using bounded_bilinear_scaleR @@ -1714,48 +1669,53 @@ lemma bounded_linear_of_real: "bounded_linear (\r. of_real r)" unfolding of_real_def by (rule bounded_linear_scaleR_left) -lemma real_bounded_linear: - fixes f :: "real \ real" - shows "bounded_linear f \ (\c::real. f = (\x. x * c))" +lemma real_bounded_linear: "bounded_linear f \ (\c::real. f = (\x. x * c))" + for f :: "real \ real" proof - - { fix x assume "bounded_linear f" + { + fix x + assume "bounded_linear f" then interpret bounded_linear f . from scaleR[of x 1] have "f x = x * f 1" - by simp } + by simp + } then show ?thesis by (auto intro: exI[of _ "f 1"] bounded_linear_mult_left) qed -lemma bij_linear_imp_inv_linear: - assumes "linear f" "bij f" shows "linear (inv f)" - using assms unfolding linear_def linear_axioms_def additive_def - by (auto simp: bij_is_surj bij_is_inj surj_f_inv_f intro!: Hilbert_Choice.inv_f_eq) +lemma bij_linear_imp_inv_linear: "linear f \ bij f \ linear (inv f)" + by (auto simp: linear_def linear_axioms_def additive_def bij_is_surj bij_is_inj surj_f_inv_f + intro!: Hilbert_Choice.inv_f_eq) instance real_normed_algebra_1 \ perfect_space proof - fix x::'a - show "\ open {x}" - unfolding open_dist dist_norm - by (clarsimp, rule_tac x="x + of_real (e/2)" in exI, simp) + show "\ open {x}" for x :: 'a + apply (simp only: open_dist dist_norm) + apply clarsimp + apply (rule_tac x = "x + of_real (e/2)" in exI) + apply simp + done qed + subsection \Filters and Limits on Metric Space\ lemma (in metric_space) nhds_metric: "nhds x = (INF e:{0 <..}. principal {y. dist y x < e})" unfolding nhds_def proof (safe intro!: INF_eq) - fix S assume "open S" "x \ S" + fix S + assume "open S" "x \ S" then obtain e where "{y. dist y x < e} \ S" "0 < e" by (auto simp: open_dist subset_eq) then show "\e\{0<..}. principal {y. dist y x < e} \ principal S" by auto qed (auto intro!: exI[of _ "{y. dist x y < e}" for e] open_ball simp: dist_commute) -lemma (in metric_space) tendsto_iff: - "(f \ l) F \ (\e>0. eventually (\x. dist (f x) l < e) F)" +lemma (in metric_space) tendsto_iff: "(f \ l) F \ (\e>0. eventually (\x. dist (f x) l < e) F)" unfolding nhds_metric filterlim_INF filterlim_principal by auto -lemma (in metric_space) tendstoI [intro?]: "(\e. 0 < e \ eventually (\x. dist (f x) l < e) F) \ (f \ l) F" +lemma (in metric_space) tendstoI [intro?]: + "(\e. 0 < e \ eventually (\x. dist (f x) l < e) F) \ (f \ l) F" by (auto simp: tendsto_iff) lemma (in metric_space) tendstoD: "(f \ l) F \ 0 < e \ eventually (\x. dist (f x) l < e) F" @@ -1767,15 +1727,13 @@ by (subst eventually_INF_base) (auto simp: eventually_principal Bex_def subset_eq intro: exI[of _ "min a b" for a b]) -lemma eventually_at: - fixes a :: "'a :: metric_space" - shows "eventually P (at a within S) \ (\d>0. \x\S. x \ a \ dist x a < d \ P x)" - unfolding eventually_at_filter eventually_nhds_metric by auto +lemma eventually_at: "eventually P (at a within S) \ (\d>0. \x\S. x \ a \ dist x a < d \ P x)" + for a :: "'a :: metric_space" + by (auto simp: eventually_at_filter eventually_nhds_metric) -lemma eventually_at_le: - fixes a :: "'a::metric_space" - shows "eventually P (at a within S) \ (\d>0. \x\S. x \ a \ dist x a \ d \ P x)" - unfolding eventually_at_filter eventually_nhds_metric +lemma eventually_at_le: "eventually P (at a within S) \ (\d>0. \x\S. x \ a \ dist x a \ d \ P x)" + for a :: "'a::metric_space" + apply (simp only: eventually_at_filter eventually_nhds_metric) apply auto apply (rule_tac x="d / 2" in exI) apply auto @@ -1788,19 +1746,21 @@ by (subst eventually_at, rule exI[of _ "b - a"]) (force simp: dist_real_def) lemma metric_tendsto_imp_tendsto: - fixes a :: "'a :: metric_space" and b :: "'b :: metric_space" + fixes a :: "'a :: metric_space" + and b :: "'b :: metric_space" assumes f: "(f \ a) F" - assumes le: "eventually (\x. dist (g x) b \ dist (f x) a) F" + and le: "eventually (\x. dist (g x) b \ dist (f x) a) F" shows "(g \ b) F" proof (rule tendstoI) - fix e :: real assume "0 < e" + fix e :: real + assume "0 < e" with f have "eventually (\x. dist (f x) a < e) F" by (rule tendstoD) with le show "eventually (\x. dist (g x) b < e) F" using le_less_trans by (rule eventually_elim2) qed lemma filterlim_real_sequentially: "LIM x sequentially. real x :> at_top" - unfolding filterlim_at_top + apply (simp only: filterlim_at_top) apply (intro allI) apply (rule_tac c="nat \Z + 1\" in eventually_sequentiallyI) apply linarith @@ -1809,73 +1769,79 @@ subsubsection \Limits of Sequences\ -lemma lim_sequentially: "X \ (L::'a::metric_space) \ (\r>0. \no. \n\no. dist (X n) L < r)" +lemma lim_sequentially: "X \ L \ (\r>0. \no. \n\no. dist (X n) L < r)" + for L :: "'a::metric_space" unfolding tendsto_iff eventually_sequentially .. lemmas LIMSEQ_def = lim_sequentially (*legacy binding*) -lemma LIMSEQ_iff_nz: "X \ (L::'a::metric_space) = (\r>0. \no>0. \n\no. dist (X n) L < r)" +lemma LIMSEQ_iff_nz: "X \ L \ (\r>0. \no>0. \n\no. dist (X n) L < r)" + for L :: "'a::metric_space" unfolding lim_sequentially by (metis Suc_leD zero_less_Suc) -lemma metric_LIMSEQ_I: - "(\r. 0 < r \ \no. \n\no. dist (X n) L < r) \ X \ (L::'a::metric_space)" -by (simp add: lim_sequentially) +lemma metric_LIMSEQ_I: "(\r. 0 < r \ \no. \n\no. dist (X n) L < r) \ X \ L" + for L :: "'a::metric_space" + by (simp add: lim_sequentially) -lemma metric_LIMSEQ_D: - "\X \ (L::'a::metric_space); 0 < r\ \ \no. \n\no. dist (X n) L < r" -by (simp add: lim_sequentially) +lemma metric_LIMSEQ_D: "X \ L \ 0 < r \ \no. \n\no. dist (X n) L < r" + for L :: "'a::metric_space" + by (simp add: lim_sequentially) subsubsection \Limits of Functions\ -lemma LIM_def: "f \(a::'a::metric_space)\ (L::'b::metric_space) = - (\r > 0. \s > 0. \x. x \ a & dist x a < s - --> dist (f x) L < r)" +lemma LIM_def: "f \a\ L \ (\r > 0. \s > 0. \x. x \ a \ dist x a < s \ dist (f x) L < r)" + for a :: "'a::metric_space" and L :: "'b::metric_space" unfolding tendsto_iff eventually_at by simp lemma metric_LIM_I: - "(\r. 0 < r \ \s>0. \x. x \ a \ dist x a < s \ dist (f x) L < r) - \ f \(a::'a::metric_space)\ (L::'b::metric_space)" -by (simp add: LIM_def) + "(\r. 0 < r \ \s>0. \x. x \ a \ dist x a < s \ dist (f x) L < r) \ f \a\ L" + for a :: "'a::metric_space" and L :: "'b::metric_space" + by (simp add: LIM_def) -lemma metric_LIM_D: - "\f \(a::'a::metric_space)\ (L::'b::metric_space); 0 < r\ - \ \s>0. \x. x \ a \ dist x a < s \ dist (f x) L < r" -by (simp add: LIM_def) +lemma metric_LIM_D: "f \a\ L \ 0 < r \ \s>0. \x. x \ a \ dist x a < s \ dist (f x) L < r" + for a :: "'a::metric_space" and L :: "'b::metric_space" + by (simp add: LIM_def) lemma metric_LIM_imp_LIM: - assumes f: "f \a\ (l::'a::metric_space)" - assumes le: "\x. x \ a \ dist (g x) m \ dist (f x) l" - shows "g \a\ (m::'b::metric_space)" + fixes l :: "'a::metric_space" + and m :: "'b::metric_space" + assumes f: "f \a\ l" + and le: "\x. x \ a \ dist (g x) m \ dist (f x) l" + shows "g \a\ m" by (rule metric_tendsto_imp_tendsto [OF f]) (auto simp add: eventually_at_topological le) lemma metric_LIM_equal2: - assumes 1: "0 < R" - assumes 2: "\x. \x \ a; dist x a < R\ \ f x = g x" - shows "g \a\ l \ f \(a::'a::metric_space)\ l" -apply (rule topological_tendstoI) -apply (drule (2) topological_tendstoD) -apply (simp add: eventually_at, safe) -apply (rule_tac x="min d R" in exI, safe) -apply (simp add: 1) -apply (simp add: 2) -done + fixes a :: "'a::metric_space" + assumes "0 < R" + and "\x. x \ a \ dist x a < R \ f x = g x" + shows "g \a\ l \ f \a\ l" + apply (rule topological_tendstoI) + apply (drule (2) topological_tendstoD) + apply (simp add: eventually_at) + apply safe + apply (rule_tac x="min d R" in exI) + apply safe + apply (simp add: assms(1)) + apply (simp add: assms(2)) + done lemma metric_LIM_compose2: - assumes f: "f \(a::'a::metric_space)\ b" - assumes g: "g \b\ c" - assumes inj: "\d>0. \x. x \ a \ dist x a < d \ f x \ b" + fixes a :: "'a::metric_space" + assumes f: "f \a\ b" + and g: "g \b\ c" + and inj: "\d>0. \x. x \ a \ dist x a < d \ f x \ b" shows "(\x. g (f x)) \a\ c" - using inj - by (intro tendsto_compose_eventually[OF g f]) (auto simp: eventually_at) + using inj by (intro tendsto_compose_eventually[OF g f]) (auto simp: eventually_at) lemma metric_isCont_LIM_compose2: fixes f :: "'a :: metric_space \ _" assumes f [unfolded isCont_def]: "isCont f a" - assumes g: "g \f a\ l" - assumes inj: "\d>0. \x. x \ a \ dist x a < d \ f x \ f a" + and g: "g \f a\ l" + and inj: "\d>0. \x. x \ a \ dist x a < d \ f x \ f a" shows "(\x. g (f x)) \a\ l" -by (rule metric_LIM_compose2 [OF f g inj]) + by (rule metric_LIM_compose2 [OF f g inj]) + subsection \Complete metric spaces\ @@ -1883,12 +1849,14 @@ lemma (in metric_space) Cauchy_def: "Cauchy X = (\e>0. \M. \m\M. \n\M. dist (X m) (X n) < e)" proof - - have *: "eventually P (INF M. principal {(X m, X n) | n m. m \ M \ n \ M}) = + have *: "eventually P (INF M. principal {(X m, X n) | n m. m \ M \ n \ M}) \ (\M. \m\M. \n\M. P (X m, X n))" for P - proof (subst eventually_INF_base, goal_cases) - case (2 a b) then show ?case + apply (subst eventually_INF_base) + subgoal by simp + subgoal for a b by (intro bexI[of _ "max a b"]) (auto simp: eventually_principal subset_eq) - qed (auto simp: eventually_principal, blast) + subgoal by (auto simp: eventually_principal, blast) + done have "Cauchy X \ (INF M. principal {(X m, X n) | n m. m \ M \ n \ M}) \ uniformity" unfolding Cauchy_uniform_iff le_filter_def * .. also have "\ = (\e>0. \M. \m\M. \n\M. dist (X m) (X n) < e)" @@ -1896,26 +1864,31 @@ finally show ?thesis . qed -lemma (in metric_space) Cauchy_altdef: - "Cauchy f = (\e>0. \M. \m\M. \n>m. dist (f m) (f n) < e)" +lemma (in metric_space) Cauchy_altdef: "Cauchy f \ (\e>0. \M. \m\M. \n>m. dist (f m) (f n) < e)" + (is "?lhs \ ?rhs") proof - assume A: "\e>0. \M. \m\M. \n>m. dist (f m) (f n) < e" - show "Cauchy f" unfolding Cauchy_def + assume ?rhs + show ?lhs + unfolding Cauchy_def proof (intro allI impI) fix e :: real assume e: "e > 0" - with A obtain M where M: "\m n. m \ M \ n > m \ dist (f m) (f n) < e" by blast + with \?rhs\ obtain M where M: "m \ M \ n > m \ dist (f m) (f n) < e" for m n + by blast have "dist (f m) (f n) < e" if "m \ M" "n \ M" for m n using M[of m n] M[of n m] e that by (cases m n rule: linorder_cases) (auto simp: dist_commute) - thus "\M. \m\M. \n\M. dist (f m) (f n) < e" by blast + then show "\M. \m\M. \n\M. dist (f m) (f n) < e" + by blast qed next - assume "Cauchy f" - show "\e>0. \M. \m\M. \n>m. dist (f m) (f n) < e" + assume ?lhs + show ?rhs proof (intro allI impI) - fix e :: real assume e: "e > 0" + fix e :: real + assume e: "e > 0" with \Cauchy f\ obtain M where "\m n. m \ M \ n \ M \ dist (f m) (f n) < e" unfolding Cauchy_def by blast - thus "\M. \m\M. \n>m. dist (f m) (f n) < e" by (intro exI[of _ M]) force + then show "\M. \m\M. \n>m. dist (f m) (f n) < e" + by (intro exI[of _ M]) force qed qed @@ -1923,7 +1896,8 @@ "(\e. 0 < e \ \M. \m\M. \n\M. dist (X m) (X n) < e) \ Cauchy X" by (simp add: Cauchy_def) -lemma (in metric_space) CauchyI': "(\e. 0 < e \ \M. \m\M. \n>m. dist (X m) (X n) < e) \ Cauchy X" +lemma (in metric_space) CauchyI': + "(\e. 0 < e \ \M. \m\M. \n>m. dist (X m) (X n) < e) \ Cauchy X" unfolding Cauchy_altdef by blast lemma (in metric_space) metric_CauchyD: @@ -1932,53 +1906,63 @@ lemma (in metric_space) metric_Cauchy_iff2: "Cauchy X = (\j. (\M. \m \ M. \n \ M. dist (X m) (X n) < inverse(real (Suc j))))" -apply (simp add: Cauchy_def, auto) -apply (drule reals_Archimedean, safe) -apply (drule_tac x = n in spec, auto) -apply (rule_tac x = M in exI, auto) -apply (drule_tac x = m in spec, simp) -apply (drule_tac x = na in spec, auto) -done + apply (simp add: Cauchy_def) + apply auto + apply (drule reals_Archimedean) + apply safe + apply (drule_tac x = n in spec) + apply auto + apply (rule_tac x = M in exI) + apply auto + apply (drule_tac x = m in spec) + apply simp + apply (drule_tac x = na in spec) + apply auto + done -lemma Cauchy_iff2: - "Cauchy X = (\j. (\M. \m \ M. \n \ M. \X m - X n\ < inverse(real (Suc j))))" - unfolding metric_Cauchy_iff2 dist_real_def .. +lemma Cauchy_iff2: "Cauchy X \ (\j. (\M. \m \ M. \n \ M. \X m - X n\ < inverse (real (Suc j))))" + by (simp only: metric_Cauchy_iff2 dist_real_def) lemma lim_1_over_n: "((\n. 1 / of_nat n) \ (0::'a::real_normed_field)) sequentially" proof (subst lim_sequentially, intro allI impI exI) - fix e :: real assume e: "e > 0" - fix n :: nat assume n: "n \ nat \inverse e + 1\" + fix e :: real + assume e: "e > 0" + fix n :: nat + assume n: "n \ nat \inverse e + 1\" have "inverse e < of_nat (nat \inverse e + 1\)" by linarith also note n - finally show "dist (1 / of_nat n :: 'a) 0 < e" using e - by (simp add: divide_simps mult.commute norm_divide) + finally show "dist (1 / of_nat n :: 'a) 0 < e" + using e by (simp add: divide_simps mult.commute norm_divide) qed lemma (in metric_space) complete_def: shows "complete S = (\f. (\n. f n \ S) \ Cauchy f \ (\l\S. f \ l))" unfolding complete_uniform proof safe - fix f :: "nat \ 'a" assume f: "\n. f n \ S" "Cauchy f" + fix f :: "nat \ 'a" + assume f: "\n. f n \ S" "Cauchy f" and *: "\F\principal S. F \ bot \ cauchy_filter F \ (\x\S. F \ nhds x)" then show "\l\S. f \ l" unfolding filterlim_def using f by (intro *[rule_format]) (auto simp: filtermap_sequentually_ne_bot le_principal eventually_filtermap Cauchy_uniform) next - fix F :: "'a filter" assume "F \ principal S" "F \ bot" "cauchy_filter F" + fix F :: "'a filter" + assume "F \ principal S" "F \ bot" "cauchy_filter F" assume seq: "\f. (\n. f n \ S) \ Cauchy f \ (\l\S. f \ l)" - from \F \ principal S\ \cauchy_filter F\ have FF_le: "F \\<^sub>F F \ uniformity_on S" + from \F \ principal S\ \cauchy_filter F\ + have FF_le: "F \\<^sub>F F \ uniformity_on S" by (simp add: cauchy_filter_def principal_prod_principal[symmetric] prod_filter_mono) let ?P = "\P e. eventually P F \ (\x. P x \ x \ S) \ (\x y. P x \ P y \ dist x y < e)" - - { fix \ :: real assume "0 < \" - then have "eventually (\(x, y). x \ S \ y \ S \ dist x y < \) (uniformity_on S)" - unfolding eventually_inf_principal eventually_uniformity_metric by auto - from filter_leD[OF FF_le this] have "\P. ?P P \" - unfolding eventually_prod_same by auto } - note P = this + have P: "\P. ?P P \" if "0 < \" for \ :: real + proof - + from that have "eventually (\(x, y). x \ S \ y \ S \ dist x y < \) (uniformity_on S)" + by (auto simp: eventually_inf_principal eventually_uniformity_metric) + from filter_leD[OF FF_le this] show ?thesis + by (auto simp: eventually_prod_same) + qed have "\P. \n. ?P (P n) (1 / Suc n) \ P (Suc n) \ P n" proof (rule dependent_nat_choice) @@ -1991,18 +1975,20 @@ ultimately show "\Q. ?P Q (1 / Suc (Suc n)) \ Q \ P" by (intro exI[of _ "\x. P x \ Q x"]) (auto simp: eventually_conj_iff) qed - then obtain P where P: "\n. eventually (P n) F" "\n x. P n x \ x \ S" - "\n x y. P n x \ P n y \ dist x y < 1 / Suc n" "\n. P (Suc n) \ P n" + then obtain P where P: "eventually (P n) F" "P n x \ x \ S" + "P n x \ P n y \ dist x y < 1 / Suc n" "P (Suc n) \ P n" + for n x y by metis have "antimono P" using P(4) unfolding decseq_Suc_iff le_fun_def by blast - obtain X where X: "\n. P n (X n)" + obtain X where X: "P n (X n)" for n using P(1)[THEN eventually_happens'[OF \F \ bot\]] by metis have "Cauchy X" unfolding metric_Cauchy_iff2 inverse_eq_divide proof (intro exI allI impI) - fix j m n :: nat assume "j \ m" "j \ n" + fix j m n :: nat + assume "j \ m" "j \ n" with \antimono P\ X have "P j (X m)" "P j (X n)" by (auto simp: antimono_def) then show "dist (X m) (X n) < 1 / Suc j" @@ -2015,23 +2001,27 @@ show "\x\S. F \ nhds x" proof (rule bexI) - { fix e :: real assume "0 < e" - then have "(\n. 1 / Suc n :: real) \ 0 \ 0 < e / 2" + have "eventually (\y. dist y x < e) F" if "0 < e" for e :: real + proof - + from that have "(\n. 1 / Suc n :: real) \ 0 \ 0 < e / 2" by (subst LIMSEQ_Suc_iff) (auto intro!: lim_1_over_n) then have "\\<^sub>F n in sequentially. dist (X n) x < e / 2 \ 1 / Suc n < e / 2" - using \X \ x\ unfolding tendsto_iff order_tendsto_iff[where 'a=real] eventually_conj_iff by blast + using \X \ x\ + unfolding tendsto_iff order_tendsto_iff[where 'a=real] eventually_conj_iff + by blast then obtain n where "dist x (X n) < e / 2" "1 / Suc n < e / 2" by (auto simp: eventually_sequentially dist_commute) - have "eventually (\y. dist y x < e) F" + show ?thesis using \eventually (P n) F\ proof eventually_elim - fix y assume "P n y" + case (elim y) then have "dist y (X n) < 1 / Suc n" by (intro X P) also have "\ < e / 2" by fact finally show "dist y x < e" by (rule dist_triangle_half_l) fact - qed } + qed + qed then show "F \ nhds x" unfolding nhds_metric le_INF_iff le_principal by auto qed fact @@ -2039,7 +2029,7 @@ lemma (in metric_space) totally_bounded_metric: "totally_bounded S \ (\e>0. \k. finite k \ S \ (\x\k. {y. dist x y < e}))" - unfolding totally_bounded_def eventually_uniformity_metric imp_ex + apply (simp only: totally_bounded_def eventually_uniformity_metric imp_ex) apply (subst all_comm) apply (intro arg_cong[where f=All] ext) apply safe @@ -2053,45 +2043,47 @@ done done + subsubsection \Cauchy Sequences are Convergent\ (* TODO: update to uniform_space *) class complete_space = metric_space + assumes Cauchy_convergent: "Cauchy X \ convergent X" -lemma Cauchy_convergent_iff: - fixes X :: "nat \ 'a::complete_space" - shows "Cauchy X = convergent X" -by (blast intro: Cauchy_convergent convergent_Cauchy) +lemma Cauchy_convergent_iff: "Cauchy X \ convergent X" + for X :: "nat \ 'a::complete_space" + by (blast intro: Cauchy_convergent convergent_Cauchy) + subsection \The set of real numbers is a complete metric space\ text \ -Proof that Cauchy sequences converge based on the one from -@{url "http://pirate.shu.edu/~wachsmut/ira/numseq/proofs/cauconv.html"} + Proof that Cauchy sequences converge based on the one from + @{url "http://pirate.shu.edu/~wachsmut/ira/numseq/proofs/cauconv.html"} \ text \ If sequence @{term "X"} is Cauchy, then its limit is the lub of @{term "{r::real. \N. \n\N. r < X n}"} \ - lemma increasing_LIMSEQ: fixes f :: "nat \ real" assumes inc: "\n. f n \ f (Suc n)" - and bdd: "\n. f n \ l" - and en: "\e. 0 < e \ \n. l \ f n + e" + and bdd: "\n. f n \ l" + and en: "\e. 0 < e \ \n. l \ f n + e" shows "f \ l" proof (rule increasing_tendsto) - fix x assume "x < l" + fix x + assume "x < l" with dense[of 0 "l - x"] obtain e where "0 < e" "e < l - x" by auto from en[OF \0 < e\] obtain n where "l - e \ f n" by (auto simp: field_simps) - with \e < l - x\ \0 < e\ have "x < f n" by simp + with \e < l - x\ \0 < e\ have "x < f n" + by simp with incseq_SucI[of f, OF inc] show "eventually (\n. x < f n) sequentially" by (auto simp: eventually_sequentially incseq_def intro: less_le_trans) -qed (insert bdd, auto) +qed (use bdd in auto) lemma real_Cauchy_convergent: fixes X :: "nat \ real" @@ -2099,63 +2091,66 @@ shows "convergent X" proof - define S :: "real set" where "S = {x. \N. \n\N. x < X n}" - then have mem_S: "\N x. \n\N. x < X n \ x \ S" by auto + then have mem_S: "\N x. \n\N. x < X n \ x \ S" + by auto - { fix N x assume N: "\n\N. X n < x" - fix y::real assume "y \ S" - hence "\M. \n\M. y < X n" - by (simp add: S_def) - then obtain M where "\n\M. y < X n" .. - hence "y < X (max M N)" by simp - also have "\ < x" using N by simp - finally have "y \ x" - by (rule order_less_imp_le) } - note bound_isUb = this + have bound_isUb: "y \ x" if N: "\n\N. X n < x" and "y \ S" for N and x y :: real + proof - + from that have "\M. \n\M. y < X n" + by (simp add: S_def) + then obtain M where "\n\M. y < X n" .. + then have "y < X (max M N)" by simp + also have "\ < x" using N by simp + finally show ?thesis by (rule order_less_imp_le) + qed obtain N where "\m\N. \n\N. dist (X m) (X n) < 1" using X[THEN metric_CauchyD, OF zero_less_one] by auto - hence N: "\n\N. dist (X n) (X N) < 1" by simp + then have N: "\n\N. dist (X n) (X N) < 1" by simp have [simp]: "S \ {}" proof (intro exI ex_in_conv[THEN iffD1]) from N have "\n\N. X N - 1 < X n" by (simp add: abs_diff_less_iff dist_real_def) - thus "X N - 1 \ S" by (rule mem_S) + then show "X N - 1 \ S" by (rule mem_S) qed have [simp]: "bdd_above S" proof from N have "\n\N. X n < X N + 1" by (simp add: abs_diff_less_iff dist_real_def) - thus "\s. s \ S \ s \ X N + 1" + then show "\s. s \ S \ s \ X N + 1" by (rule bound_isUb) qed have "X \ Sup S" proof (rule metric_LIMSEQ_I) - fix r::real assume "0 < r" - hence r: "0 < r/2" by simp - obtain N where "\n\N. \m\N. dist (X n) (X m) < r/2" - using metric_CauchyD [OF X r] by auto - hence "\n\N. dist (X n) (X N) < r/2" by simp - hence N: "\n\N. X N - r/2 < X n \ X n < X N + r/2" - by (simp only: dist_real_def abs_diff_less_iff) + fix r :: real + assume "0 < r" + then have r: "0 < r/2" by simp + obtain N where "\n\N. \m\N. dist (X n) (X m) < r/2" + using metric_CauchyD [OF X r] by auto + then have "\n\N. dist (X n) (X N) < r/2" by simp + then have N: "\n\N. X N - r/2 < X n \ X n < X N + r/2" + by (simp only: dist_real_def abs_diff_less_iff) - from N have "\n\N. X N - r/2 < X n" by blast - hence "X N - r/2 \ S" by (rule mem_S) - hence 1: "X N - r/2 \ Sup S" by (simp add: cSup_upper) + from N have "\n\N. X N - r/2 < X n" by blast + then have "X N - r/2 \ S" by (rule mem_S) + then have 1: "X N - r/2 \ Sup S" by (simp add: cSup_upper) - from N have "\n\N. X n < X N + r/2" by blast - from bound_isUb[OF this] - have 2: "Sup S \ X N + r/2" - by (intro cSup_least) simp_all + from N have "\n\N. X n < X N + r/2" by blast + from bound_isUb[OF this] + have 2: "Sup S \ X N + r/2" + by (intro cSup_least) simp_all - show "\N. \n\N. dist (X n) (Sup S) < r" - proof (intro exI allI impI) - fix n assume n: "N \ n" - from N n have "X n < X N + r/2" and "X N - r/2 < X n" by simp+ - thus "dist (X n) (Sup S) < r" using 1 2 - by (simp add: abs_diff_less_iff dist_real_def) + show "\N. \n\N. dist (X n) (Sup S) < r" + proof (intro exI allI impI) + fix n + assume n: "N \ n" + from N n have "X n < X N + r/2" and "X N - r/2 < X n" + by simp_all + then show "dist (X n) (Sup S) < r" using 1 2 + by (simp add: abs_diff_less_iff dist_real_def) + qed qed - qed - then show ?thesis unfolding convergent_def by auto + then show ?thesis by (auto simp: convergent_def) qed instance real :: complete_space @@ -2170,7 +2165,8 @@ assumes *: "\X. filterlim X at_top sequentially \ (\n. f (X n)) \ y" shows "(f \ y) at_top" proof - - from nhds_countable[of y] guess A . note A = this + obtain A where A: "decseq A" "open (A n)" "y \ A n" "nhds y = (INF n. principal (A n))" for n + by (rule nhds_countable[of y]) (rule that) have "\m. \k. \x\k. f x \ A m" proof (rule ccontr) @@ -2181,45 +2177,46 @@ by (intro dependent_nat_choice) (auto simp del: max.bounded_iff) then obtain X where X: "\n. f (X n) \ A m" "\n. max n (X n) + 1 \ X (Suc n)" by auto - { fix n have "1 \ n \ real n \ X n" - using X[of "n - 1"] by auto } + have "1 \ n \ real n \ X n" for n + using X[of "n - 1"] by auto then have "filterlim X at_top sequentially" by (force intro!: filterlim_at_top_mono[OF filterlim_real_sequentially] - simp: eventually_sequentially) + simp: eventually_sequentially) from topological_tendstoD[OF *[OF this] A(2, 3), of m] X(1) show False by auto qed - then obtain k where "\m x. k m \ x \ f x \ A m" + then obtain k where "k m \ x \ f x \ A m" for m x by metis then show ?thesis - unfolding at_top_def A - by (intro filterlim_base[where i=k]) auto + unfolding at_top_def A by (intro filterlim_base[where i=k]) auto qed lemma tendsto_at_topI_sequentially_real: fixes f :: "real \ real" assumes mono: "mono f" - assumes limseq: "(\n. f (real n)) \ y" + and limseq: "(\n. f (real n)) \ y" shows "(f \ y) at_top" proof (rule tendstoI) - fix e :: real assume "0 < e" - with limseq obtain N :: nat where N: "\n. N \ n \ \f (real n) - y\ < e" + fix e :: real + assume "0 < e" + with limseq obtain N :: nat where N: "N \ n \ \f (real n) - y\ < e" for n by (auto simp: lim_sequentially dist_real_def) - { fix x :: real + have le: "f x \ y" for x :: real + proof - obtain n where "x \ real_of_nat n" using real_arch_simple[of x] .. note monoD[OF mono this] also have "f (real_of_nat n) \ y" by (rule LIMSEQ_le_const[OF limseq]) (auto intro!: exI[of _ n] monoD[OF mono]) - finally have "f x \ y" . } - note le = this + finally show ?thesis . + qed have "eventually (\x. real N \ x) at_top" by (rule eventually_ge_at_top) then show "eventually (\x. dist (f x) y < e) at_top" proof eventually_elim - fix x assume N': "real N \ x" + case (elim x) with N[of N] le have "y - f (real N) < e" by auto - moreover note monoD[OF mono N'] + moreover note monoD[OF mono elim] ultimately show "dist (f x) y < e" using le[of x] by (auto simp: dist_real_def field_simps) qed