# HG changeset patch # User wenzelm # Date 1375902980 -7200 # Node ID 7196e1ce1cd825252a570a95516fe7f3eac82926 # Parent 8be75f53db82d5584b7afa8520737973b0f91b85 tuned proofs; diff -r 8be75f53db82 -r 7196e1ce1cd8 src/HOL/Library/Formal_Power_Series.thy --- a/src/HOL/Library/Formal_Power_Series.thy Wed Aug 07 20:32:54 2013 +0200 +++ b/src/HOL/Library/Formal_Power_Series.thy Wed Aug 07 21:16:20 2013 +0200 @@ -142,14 +142,7 @@ fixes k :: nat and f :: "nat \ nat \ nat \ 'a::comm_monoid_add" shows "(\j=0..k. \i=0..j. f i (j - i) (n - j)) = (\j=0..k. \i=0..k - j. f j i (n - j - i))" -proof (induct k) - case 0 - show ?case by simp -next - case (Suc k) - then show ?case - by (simp add: Suc_diff_le setsum_addf add_assoc cong: strong_setsum_cong) -qed + by (induct k) (simp_all add: Suc_diff_le setsum_addf add_assoc) instance fps :: (semiring_0) semigroup_mult proof @@ -172,7 +165,10 @@ show "inj_on (\i. n - i) {0..n}" by (rule inj_onI) simp show "{0..n} = (\i. n - i) ` {0..n}" - by (auto, rule_tac x="n - x" in image_eqI, simp_all) + apply auto + apply (rule_tac x = "n - x" in image_eqI) + apply simp_all + done next fix i assume "i \ {0..n}" @@ -209,10 +205,8 @@ instance fps :: (semiring_1) monoid_mult proof fix a :: "'a fps" - show "1 * a = a" - by (simp add: fps_ext fps_mult_nth mult_delta_left setsum_delta) - show "a * 1 = a" - by (simp add: fps_ext fps_mult_nth mult_delta_right setsum_delta') + show "1 * a = a" by (simp add: fps_ext fps_mult_nth mult_delta_left setsum_delta) + show "a * 1 = a" by (simp add: fps_ext fps_mult_nth mult_delta_right setsum_delta') qed instance fps :: (cancel_semigroup_add) cancel_semigroup_add @@ -271,8 +265,7 @@ lemma fps_nonzero_nth: "f \ 0 \ (\ n. f $n \ 0)" by (simp add: expand_fps_eq) -lemma fps_nonzero_nth_minimal: - "f \ 0 \ (\n. f $ n \ 0 \ (\m < n. f $ m = 0))" +lemma fps_nonzero_nth_minimal: "f \ 0 \ (\n. f $ n \ 0 \ (\m < n. f $ m = 0))" proof let ?n = "LEAST n. f $ n \ 0" assume "f \ 0" @@ -399,14 +392,20 @@ definition "X = Abs_fps (\n. if n = 1 then 1 else 0)" lemma X_mult_nth[simp]: "(X * (f :: ('a::semiring_1) fps)) $n = (if n = 0 then 0 else f $ (n - 1))" -proof- - {assume n: "n \ 0" - have "(X * f) $n = (\i = 0..n. X $ i * f $ (n - i))" by (simp add: fps_mult_nth) +proof - + { + assume n: "n \ 0" + have "(X * f) $n = (\i = 0..n. X $ i * f $ (n - i))" + by (simp add: fps_mult_nth) also have "\ = f $ (n - 1)" using n by (simp add: X_def mult_delta_left setsum_delta) - finally have ?thesis using n by simp } + finally have ?thesis using n by simp + } moreover - {assume n: "n=0" hence ?thesis by (simp add: fps_mult_nth X_def)} + { + assume n: "n=0" + hence ?thesis by (simp add: fps_mult_nth X_def) + } ultimately show ?thesis by blast qed @@ -415,8 +414,9 @@ by (metis X_mult_nth mult_commute) lemma X_power_iff: "X^k = Abs_fps (\n. if n = k then (1::'a::comm_ring_1) else 0)" -proof(induct k) - case 0 thus ?case by (simp add: X_def fps_eq_iff) +proof (induct k) + case 0 + thus ?case by (simp add: X_def fps_eq_iff) next case (Suc k) { @@ -443,11 +443,9 @@ by (metis X_power_mult_nth mult_commute) - - subsection{* Formal Power series form a metric space *} -definition (in dist) ball_def: "ball x r = {y. dist y x < r}" +definition (in dist) "ball x r = {y. dist y x < r}" instantiation fps :: (comm_ring_1) dist begin @@ -470,7 +468,8 @@ end -lemma fps_nonzero_least_unique: assumes a0: "a \ 0" +lemma fps_nonzero_least_unique: + assumes a0: "a \ 0" shows "\! n. leastP (\n. a$n \ 0) n" proof - from fps_nonzero_nth_minimal [of a] a0 @@ -628,8 +627,8 @@ apply (simp add: setsum_delta') done -lemma fps_notation: - "(%n. setsum (%i. fps_const(a$i) * X^i) {0..n}) ----> a" (is "?s ----> a") +lemma fps_notation: "(%n. setsum (%i. fps_const(a$i) * X^i) {0..n}) ----> a" + (is "?s ----> a") proof - { fix r:: real @@ -767,7 +766,8 @@ qed lemma fps_inverse_unique: - assumes f0: "f$0 \ (0::'a::field)" and fg: "f*g = 1" + assumes f0: "f$0 \ (0::'a::field)" + and fg: "f*g = 1" shows "inverse f = g" proof - from inverse_mult_eq_1[OF f0] fg @@ -777,7 +777,7 @@ qed lemma fps_inverse_gp: "inverse (Abs_fps(\n. (1::'a::field))) - = Abs_fps (\n. if n= 0 then 1 else if n=1 then - 1 else 0)" + = Abs_fps (\n. if n= 0 then 1 else if n=1 then - 1 else 0)" apply (rule fps_inverse_unique) apply simp apply (simp add: fps_eq_iff fps_mult_nth) @@ -910,7 +910,7 @@ lemma fps_deriv_setsum: "fps_deriv (setsum f S) = setsum (\i. fps_deriv (f i :: ('a::comm_ring_1) fps)) S" -proof- +proof - { assume "\ finite S" then have ?thesis by simp @@ -923,9 +923,9 @@ ultimately show ?thesis by blast qed -lemma fps_deriv_eq_0_iff[simp]: +lemma fps_deriv_eq_0_iff [simp]: "fps_deriv f = 0 \ (f = fps_const (f$0 :: 'a::{idom,semiring_char_0}))" -proof- +proof - { assume "f = fps_const (f$0)" then have "fps_deriv f = fps_deriv (fps_const (f$0))" by simp @@ -1114,7 +1114,7 @@ shows "a^n $ n = (a$1) ^ n" proof (induct n) case 0 - then show ?case by (simp add: power_0) + then show ?case by simp next case (Suc n) have "a ^ Suc n $ (Suc n) = (a^n * a)$(Suc n)" by (simp add: field_simps) @@ -1186,31 +1186,39 @@ unfolding power2_eq_square apply (simp add: field_simps) by (simp add: mult_assoc[symmetric]) - hence "inverse a ^ 2 * fps_deriv a + fps_deriv (inverse a) - fps_deriv a * inverse a ^ 2 = 0 - fps_deriv a * inverse a ^ 2" + hence "inverse a ^ 2 * fps_deriv a + fps_deriv (inverse a) - fps_deriv a * inverse a ^ 2 = + 0 - fps_deriv a * inverse a ^ 2" by simp - then show "fps_deriv (inverse a) = - fps_deriv a * inverse a ^ 2" by (simp add: field_simps) + then show "fps_deriv (inverse a) = - fps_deriv a * inverse a ^ 2" + by (simp add: field_simps) qed lemma fps_inverse_mult: fixes a::"('a :: field) fps" shows "inverse (a * b) = inverse a * inverse b" proof- - {assume a0: "a$0 = 0" hence ab0: "(a*b)$0 = 0" by (simp add: fps_mult_nth) + { + assume a0: "a$0 = 0" hence ab0: "(a*b)$0 = 0" by (simp add: fps_mult_nth) from a0 ab0 have th: "inverse a = 0" "inverse (a*b) = 0" by simp_all - have ?thesis unfolding th by simp} + have ?thesis unfolding th by simp + } moreover - {assume b0: "b$0 = 0" hence ab0: "(a*b)$0 = 0" by (simp add: fps_mult_nth) + { + assume b0: "b$0 = 0" hence ab0: "(a*b)$0 = 0" by (simp add: fps_mult_nth) from b0 ab0 have th: "inverse b = 0" "inverse (a*b) = 0" by simp_all - have ?thesis unfolding th by simp} + have ?thesis unfolding th by simp + } moreover - {assume a0: "a$0 \ 0" and b0: "b$0 \ 0" + { + assume a0: "a$0 \ 0" and b0: "b$0 \ 0" from a0 b0 have ab0:"(a*b) $ 0 \ 0" by (simp add: fps_mult_nth) from inverse_mult_eq_1[OF ab0] have "inverse (a*b) * (a*b) * inverse a * inverse b = 1 * inverse a * inverse b" by simp then have "inverse (a*b) * (inverse a * a) * (inverse b * b) = inverse a * inverse b" by (simp add: field_simps) - then have ?thesis using inverse_mult_eq_1[OF a0] inverse_mult_eq_1[OF b0] by simp} -ultimately show ?thesis by blast + then have ?thesis using inverse_mult_eq_1[OF a0] inverse_mult_eq_1[OF b0] by simp + } + ultimately show ?thesis by blast qed lemma fps_inverse_deriv': @@ -1221,11 +1229,13 @@ unfolding power2_eq_square fps_divide_def fps_inverse_mult by simp -lemma inverse_mult_eq_1': assumes f0: "f$0 \ (0::'a::field)" +lemma inverse_mult_eq_1': + assumes f0: "f$0 \ (0::'a::field)" shows "f * inverse f= 1" by (metis mult_commute inverse_mult_eq_1 f0) -lemma fps_divide_deriv: fixes a:: "('a :: field) fps" +lemma fps_divide_deriv: + fixes a:: "('a :: field) fps" assumes a0: "b$0 \ 0" shows "fps_deriv (a / b) = (fps_deriv a * b - a * fps_deriv b) / b ^ 2" using fps_inverse_deriv[OF a0] @@ -1233,12 +1243,11 @@ power2_eq_square fps_inverse_mult inverse_mult_eq_1'[OF a0]) -lemma fps_inverse_gp': "inverse (Abs_fps(\n. (1::'a::field))) - = 1 - X" +lemma fps_inverse_gp': "inverse (Abs_fps(\n. (1::'a::field))) = 1 - X" by (simp add: fps_inverse_gp fps_eq_iff X_def) lemma fps_nth_deriv_X[simp]: "fps_nth_deriv n X = (if n = 0 then X else if n=1 then 1 else 0)" - by (cases "n", simp_all) + by (cases n) simp_all lemma fps_inverse_X_plus1: @@ -1293,8 +1302,7 @@ unfolding neg_numeral_fps_const by simp lemma X_fps_compose_startby0[simp]: "a$0 = 0 \ X oo a = (a :: ('a :: comm_ring_1) fps)" - by (simp add: fps_eq_iff fps_compose_def mult_delta_left setsum_delta - power_Suc not_le) + by (simp add: fps_eq_iff fps_compose_def mult_delta_left setsum_delta not_le) subsection {* Rules from Herbert Wilf's Generatingfunctionology*} @@ -1303,29 +1311,35 @@ (* {a_{n+k}}_0^infty Corresponds to (f - setsum (\i. a_i * x^i))/x^h, for h>0*) lemma fps_power_mult_eq_shift: - "X^Suc k * Abs_fps (\n. a (n + Suc k)) = Abs_fps a - setsum (\i. fps_const (a i :: 'a:: comm_ring_1) * X^i) {0 .. k}" (is "?lhs = ?rhs") -proof- - {fix n:: nat + "X^Suc k * Abs_fps (\n. a (n + Suc k)) = + Abs_fps a - setsum (\i. fps_const (a i :: 'a:: comm_ring_1) * X^i) {0 .. k}" + (is "?lhs = ?rhs") +proof - + { fix n:: nat have "?lhs $ n = (if n < Suc k then 0 else a n)" unfolding X_power_mult_nth by auto also have "\ = ?rhs $ n" - proof(induct k) - case 0 thus ?case by (simp add: fps_setsum_nth power_Suc) + proof (induct k) + case 0 + thus ?case by (simp add: fps_setsum_nth) next case (Suc k) note th = Suc.hyps[symmetric] - have "(Abs_fps a - setsum (\i. fps_const (a i :: 'a) * X^i) {0 .. Suc k})$n = (Abs_fps a - setsum (\i. fps_const (a i :: 'a) * X^i) {0 .. k} - fps_const (a (Suc k)) * X^ Suc k) $ n" by (simp add: field_simps) - also have "\ = (if n < Suc k then 0 else a n) - (fps_const (a (Suc k)) * X^ Suc k)$n" - using th - unfolding fps_sub_nth by simp + have "(Abs_fps a - setsum (\i. fps_const (a i :: 'a) * X^i) {0 .. Suc k})$n = + (Abs_fps a - setsum (\i. fps_const (a i :: 'a) * X^i) {0 .. k} - fps_const (a (Suc k)) * X^ Suc k) $ n" + by (simp add: field_simps) + also have "\ = (if n < Suc k then 0 else a n) - (fps_const (a (Suc k)) * X^ Suc k)$n" + using th unfolding fps_sub_nth by simp also have "\ = (if n < Suc (Suc k) then 0 else a n)" unfolding X_power_mult_right_nth apply (auto simp add: not_less fps_const_def) apply (rule cong[of a a, OF refl]) - by arith + apply arith + done finally show ?case by simp qed - finally have "?lhs $ n = ?rhs $ n" .} + finally have "?lhs $ n = ?rhs $ n" . + } then show ?thesis by (simp add: fps_eq_iff) qed @@ -1343,19 +1357,22 @@ lemma XD_mult_const[simp]:"XD (fps_const (c::'a::comm_ring_1) * a) = fps_const c * XD a" by (simp add: XD_def field_simps) -lemma XD_linear[simp]: "XD (fps_const c * a + fps_const d * b) = fps_const c * XD a + fps_const d * XD (b :: ('a::comm_ring_1) fps)" +lemma XD_linear[simp]: "XD (fps_const c * a + fps_const d * b) = + fps_const c * XD a + fps_const d * XD (b :: ('a::comm_ring_1) fps)" by simp lemma XDN_linear: - "(XD ^^ n) (fps_const c * a + fps_const d * b) = fps_const c * (XD ^^ n) a + fps_const d * (XD ^^ n) (b :: ('a::comm_ring_1) fps)" + "(XD ^^ n) (fps_const c * a + fps_const d * b) = + fps_const c * (XD ^^ n) a + fps_const d * (XD ^^ n) (b :: ('a::comm_ring_1) fps)" by (induct n) simp_all -lemma fps_mult_X_deriv_shift: "X* fps_deriv a = Abs_fps (\n. of_nat n* a$n)" by (simp add: fps_eq_iff) +lemma fps_mult_X_deriv_shift: "X* fps_deriv a = Abs_fps (\n. of_nat n* a$n)" + by (simp add: fps_eq_iff) lemma fps_mult_XD_shift: "(XD ^^ k) (a:: ('a::{comm_ring_1}) fps) = Abs_fps (\n. (of_nat n ^ k) * a$n)" - by (induct k arbitrary: a) (simp_all add: power_Suc XD_def fps_eq_iff field_simps del: One_nat_def) + by (induct k arbitrary: a) (simp_all add: XD_def fps_eq_iff field_simps del: One_nat_def) subsubsection{* Rule 3 is trivial and is given by @{text fps_times_def}*} subsubsection{* Rule 5 --- summation and "division" by (1 - X)*} @@ -1365,12 +1382,18 @@ proof- let ?X = "X::('a::comm_ring_1) fps" let ?sa = "Abs_fps (\n. setsum (\i. a $ i) {0..n})" - have th0: "\i. (1 - (X::'a fps)) $ i = (if i = 0 then 1 else if i = 1 then - 1 else 0)" by simp - {fix n:: nat - {assume "n=0" hence "a$n = ((1 - ?X) * ?sa) $ n" - by (simp add: fps_mult_nth)} + have th0: "\i. (1 - (X::'a fps)) $ i = (if i = 0 then 1 else if i = 1 then - 1 else 0)" + by simp + { + fix n:: nat + { + assume "n=0" + hence "a$n = ((1 - ?X) * ?sa) $ n" + by (simp add: fps_mult_nth) + } moreover - {assume n0: "n \ 0" + { + assume n0: "n \ 0" then have u: "{0} \ ({1} \ {2..n}) = {0..n}" "{1}\{2..n} = {1..n}" "{0..n - 1}\{n} = {0..n}" by (auto simp: set_eq_iff) @@ -1378,23 +1401,26 @@ "{0..n - 1}\{n} ={}" using n0 by simp_all have f: "finite {0}" "finite {1}" "finite {2 .. n}" "finite {0 .. n - 1}" "finite {n}" by simp_all - have "((1 - ?X) * ?sa) $ n = setsum (\i. (1 - ?X)$ i * ?sa $ (n - i)) {0 .. n}" - by (simp add: fps_mult_nth) - also have "\ = a$n" unfolding th0 - unfolding setsum_Un_disjoint[OF f(1) finite_UnI[OF f(2,3)] d(1), unfolded u(1)] - unfolding setsum_Un_disjoint[OF f(2) f(3) d(2)] - apply (simp) - unfolding setsum_Un_disjoint[OF f(4,5) d(3), unfolded u(3)] - by simp - finally have "a$n = ((1 - ?X) * ?sa) $ n" by simp} - ultimately have "a$n = ((1 - ?X) * ?sa) $ n" by blast} -then show ?thesis - unfolding fps_eq_iff by blast + have "((1 - ?X) * ?sa) $ n = setsum (\i. (1 - ?X)$ i * ?sa $ (n - i)) {0 .. n}" + by (simp add: fps_mult_nth) + also have "\ = a$n" + unfolding th0 + unfolding setsum_Un_disjoint[OF f(1) finite_UnI[OF f(2,3)] d(1), unfolded u(1)] + unfolding setsum_Un_disjoint[OF f(2) f(3) d(2)] + apply (simp) + unfolding setsum_Un_disjoint[OF f(4,5) d(3), unfolded u(3)] + apply simp + done + finally have "a$n = ((1 - ?X) * ?sa) $ n" by simp + } + ultimately have "a$n = ((1 - ?X) * ?sa) $ n" by blast + } + then show ?thesis unfolding fps_eq_iff by blast qed lemma fps_divide_X_minus1_setsum: "a /((1::('a::field) fps) - X) = Abs_fps (\n. setsum (\i. a $ i) {0..n})" -proof- +proof - let ?X = "1 - (X::('a::field) fps)" have th0: "?X $ 0 \ 0" by simp have "a /?X = ?X * Abs_fps (\n\nat. setsum (op $ a) {0..n}) * inverse ?X" @@ -1412,27 +1438,37 @@ lemma natlist_trivial_1: "natpermute n 1 = {[n]}" apply (auto simp add: natpermute_def) - apply (case_tac x, auto) + apply (case_tac x) + apply auto done lemma append_natpermute_less_eq: - assumes h: "xs@ys \ natpermute n k" shows "listsum xs \ n" and "listsum ys \ n" -proof- - {from h have "listsum (xs @ ys) = n" by (simp add: natpermute_def) - hence "listsum xs + listsum ys = n" by simp} - note th = this - {from th show "listsum xs \ n" by simp} - {from th show "listsum ys \ n" by simp} + assumes h: "xs@ys \ natpermute n k" + shows "listsum xs \ n" and "listsum ys \ n" +proof - + from h have "listsum (xs @ ys) = n" by (simp add: natpermute_def) + hence *: "listsum xs + listsum ys = n" by simp + from * show "listsum xs \ n" by simp + from * show "listsum ys \ n" by simp qed lemma natpermute_split: assumes mn: "h \ k" - shows "natpermute n k = (\m \{0..n}. {l1 @ l2 |l1 l2. l1 \ natpermute m h \ l2 \ natpermute (n - m) (k - h)})" (is "?L = ?R" is "?L = (\m \{0..n}. ?S m)") -proof- - {fix l assume l: "l \ ?R" - from l obtain m xs ys where h: "m \ {0..n}" and xs: "xs \ natpermute m h" and ys: "ys \ natpermute (n - m) (k - h)" and leq: "l = xs@ys" by blast - from xs have xs': "listsum xs = m" by (simp add: natpermute_def) - from ys have ys': "listsum ys = n - m" by (simp add: natpermute_def) + shows "natpermute n k = + (\m \{0..n}. {l1 @ l2 |l1 l2. l1 \ natpermute m h \ l2 \ natpermute (n - m) (k - h)})" + (is "?L = ?R" is "?L = (\m \{0..n}. ?S m)") +proof - + { + fix l + assume l: "l \ ?R" + from l obtain m xs ys where h: "m \ {0..n}" + and xs: "xs \ natpermute m h" + and ys: "ys \ natpermute (n - m) (k - h)" + and leq: "l = xs@ys" by blast + from xs have xs': "listsum xs = m" + by (simp add: natpermute_def) + from ys have ys': "listsum ys = n - m" + by (simp add: natpermute_def) have "l \ ?L" using leq xs ys h apply (clarsimp simp add: natpermute_def) unfolding xs' ys' @@ -1442,21 +1478,27 @@ done } moreover - {fix l assume l: "l \ natpermute n k" + { + fix l + assume l: "l \ natpermute n k" let ?xs = "take h l" let ?ys = "drop h l" let ?m = "listsum ?xs" - from l have ls: "listsum (?xs @ ?ys) = n" by (simp add: natpermute_def) - have xs: "?xs \ natpermute ?m h" using l mn by (simp add: natpermute_def) - have l_take_drop: "listsum l = listsum (take h l @ drop h l)" by simp - then have ys: "?ys \ natpermute (n - ?m) (k - h)" using l mn ls - by (auto simp add: natpermute_def simp del: append_take_drop_id) - from ls have m: "?m \ {0..n}" by (simp add: l_take_drop del: append_take_drop_id) + from l have ls: "listsum (?xs @ ?ys) = n" + by (simp add: natpermute_def) + have xs: "?xs \ natpermute ?m h" using l mn + by (simp add: natpermute_def) + have l_take_drop: "listsum l = listsum (take h l @ drop h l)" + by simp + then have ys: "?ys \ natpermute (n - ?m) (k - h)" + using l mn ls by (auto simp add: natpermute_def simp del: append_take_drop_id) + from ls have m: "?m \ {0..n}" + by (simp add: l_take_drop del: append_take_drop_id) from xs ys ls have "l \ ?R" apply auto - apply (rule bexI[where x = "?m"]) - apply (rule exI[where x = "?xs"]) - apply (rule exI[where x = "?ys"]) + apply (rule bexI [where x = "?m"]) + apply (rule exI [where x = "?xs"]) + apply (rule exI [where x = "?ys"]) using ls l apply (auto simp add: natpermute_def l_take_drop simp del: append_take_drop_id) apply simp @@ -1467,6 +1509,7 @@ lemma natpermute_0: "natpermute n 0 = (if n = 0 then {[]} else {})" by (auto simp add: natpermute_def) + lemma natpermute_0'[simp]: "natpermute 0 k = (if k = 0 then {[]} else {replicate k 0})" apply (auto simp add: set_replicate_conv_if natpermute_def) apply (rule nth_equalityI) @@ -1474,13 +1517,15 @@ done lemma natpermute_finite: "finite (natpermute n k)" -proof(induct k arbitrary: n) - case 0 thus ?case +proof (induct k arbitrary: n) + case 0 + then show ?case apply (subst natpermute_split[of 0 0, simplified]) - by (simp add: natpermute_0) + apply (simp add: natpermute_0) + done next case (Suc k) - then show ?case unfolding natpermute_split[of k "Suc k", simplified] + then show ?case unfolding natpermute_split [of k "Suc k", simplified] apply - apply (rule finite_UN_I) apply simp @@ -1493,20 +1538,29 @@ "{xs \ natpermute n (k+1). n \ set xs} = UNION {0 .. k} (\i. {(replicate (k+1) 0) [i:=n]})" (is "?A = ?B") proof- - {fix xs assume H: "xs \ natpermute n (k+1)" and n: "n \ set xs" + { + fix xs + assume H: "xs \ natpermute n (k+1)" and n: "n \ set xs" from n obtain i where i: "i \ {0.. k}" "xs!i = n" using H unfolding in_set_conv_nth by (auto simp add: less_Suc_eq_le natpermute_def) - have eqs: "({0..k} - {i}) \ {i} = {0..k}" using i by auto - have f: "finite({0..k} - {i})" "finite {i}" by auto - have d: "({0..k} - {i}) \ {i} = {}" using i by auto - from H have "n = setsum (nth xs) {0..k}" apply (simp add: natpermute_def) - by (auto simp add: atLeastLessThanSuc_atLeastAtMost listsum_setsum_nth) + have eqs: "({0..k} - {i}) \ {i} = {0..k}" + using i by auto + have f: "finite({0..k} - {i})" "finite {i}" + by auto + have d: "({0..k} - {i}) \ {i} = {}" + using i by auto + from H have "n = setsum (nth xs) {0..k}" + apply (simp add: natpermute_def) + apply (auto simp add: atLeastLessThanSuc_atLeastAtMost listsum_setsum_nth) + done also have "\ = n + setsum (nth xs) ({0..k} - {i})" unfolding setsum_Un_disjoint[OF f d, unfolded eqs] using i by simp - finally have zxs: "\ j\ {0..k} - {i}. xs!j = 0" by auto - from H have xsl: "length xs = k+1" by (simp add: natpermute_def) + finally have zxs: "\ j\ {0..k} - {i}. xs!j = 0" + by auto + from H have xsl: "length xs = k+1" + by (simp add: natpermute_def) from i have i': "i < length (replicate (k+1) 0)" "i < k+1" - unfolding length_replicate by arith+ + unfolding length_replicate by presburger+ have "xs = replicate (k+1) 0 [i := n]" apply (rule nth_equalityI) unfolding xsl length_list_update length_replicate @@ -1514,42 +1568,56 @@ apply clarify unfolding nth_list_update[OF i'(1)] using i zxs - by (case_tac "ia=i", auto simp del: replicate.simps) + apply (case_tac "ia = i") + apply (auto simp del: replicate.simps) + done then have "xs \ ?B" using i by blast } moreover - {fix i assume i: "i \ {0..k}" + { + fix i + assume i: "i \ {0..k}" let ?xs = "replicate (k+1) 0 [i:=n]" have nxs: "n \ set ?xs" - apply (rule set_update_memI) using i by simp - have xsl: "length ?xs = k+1" by (simp only: length_replicate length_list_update) + apply (rule set_update_memI) + using i apply simp + done + have xsl: "length ?xs = k+1" + by (simp only: length_replicate length_list_update) have "listsum ?xs = setsum (nth ?xs) {0.. = setsum (\j. if j = i then n else 0) {0..< k+1}" - apply (rule setsum_cong2) by (simp del: replicate.simps) + by (rule setsum_cong2) (simp del: replicate.simps) also have "\ = n" using i by (simp add: setsum_delta) - finally - have "?xs \ natpermute n (k+1)" using xsl unfolding natpermute_def mem_Collect_eq - by blast - then have "?xs \ ?A" using nxs by blast + finally have "?xs \ natpermute n (k+1)" + using xsl unfolding natpermute_def mem_Collect_eq by blast + then have "?xs \ ?A" + using nxs by blast } ultimately show ?thesis by auto qed (* The general form *) lemma fps_setprod_nth: - fixes m :: nat and a :: "nat \ ('a::comm_ring_1) fps" + fixes m :: nat + and a :: "nat \ ('a::comm_ring_1) fps" shows "(setprod a {0 .. m})$n = setsum (\v. setprod (\j. (a j) $ (v!j)) {0..m}) (natpermute n (m+1))" (is "?P m n") -proof(induct m arbitrary: n rule: nat_less_induct) +proof (induct m arbitrary: n rule: nat_less_induct) fix m n assume H: "\m' < m. \n. ?P m' n" - {assume m0: "m = 0" + { + assume m0: "m = 0" hence "?P m n" apply simp - unfolding natlist_trivial_1[where n = n, unfolded One_nat_def] by simp} + unfolding natlist_trivial_1[where n = n, unfolded One_nat_def] by simp + } moreover - {fix k assume k: "m = Suc k" + { + fix k assume k: "m = Suc k" have km: "k < m" using k by arith - have u0: "{0 .. k} \ {m} = {0..m}" using k apply (simp add: set_eq_iff) by presburger + have u0: "{0 .. k} \ {m} = {0..m}" + using k apply (simp add: set_eq_iff) + apply presburger + done have f0: "finite {0 .. k}" "finite {m}" by auto have d0: "{0 .. k} \ {m} = {}" using k by auto have "(setprod a {0 .. m}) $ n = (setprod a {0 .. k} * a m) $ n" @@ -1587,54 +1655,65 @@ lemma fps_power_nth_Suc: fixes m :: nat and a :: "('a::comm_ring_1) fps" shows "(a ^ Suc m)$n = setsum (\v. setprod (\j. a $ (v!j)) {0..m}) (natpermute n (m+1))" -proof- +proof - have th0: "a^Suc m = setprod (\i. a) {0..m}" by (simp add: setprod_constant) show ?thesis unfolding th0 fps_setprod_nth .. qed + lemma fps_power_nth: fixes m :: nat and a :: "('a::comm_ring_1) fps" shows "(a ^m)$n = (if m=0 then 1$n else setsum (\v. setprod (\j. a $ (v!j)) {0..m - 1}) (natpermute n m))" - by (cases m, simp_all add: fps_power_nth_Suc del: power_Suc) + by (cases m) (simp_all add: fps_power_nth_Suc del: power_Suc) lemma fps_nth_power_0: fixes m :: nat and a :: "('a::{comm_ring_1}) fps" shows "(a ^m)$0 = (a$0) ^ m" -proof- - {assume "m=0" hence ?thesis by simp} +proof - + { + assume "m = 0" + hence ?thesis by simp + } moreover - {fix n assume m: "m = Suc n" + { + fix n + assume m: "m = Suc n" have c: "m = card {0..n}" using m by simp - have "(a ^m)$0 = setprod (\i. a$0) {0..n}" - by (simp add: m fps_power_nth del: replicate.simps power_Suc) - also have "\ = (a$0) ^ m" - unfolding c by (rule setprod_constant, simp) - finally have ?thesis .} - ultimately show ?thesis by (cases m, auto) + have "(a ^m)$0 = setprod (\i. a$0) {0..n}" + by (simp add: m fps_power_nth del: replicate.simps power_Suc) + also have "\ = (a$0) ^ m" + unfolding c by (rule setprod_constant) simp + finally have ?thesis . + } + ultimately show ?thesis by (cases m) auto qed lemma fps_compose_inj_right: assumes a0: "a$0 = (0::'a::{idom})" - and a1: "a$1 \ 0" + and a1: "a$1 \ 0" shows "(b oo a = c oo a) \ b = c" (is "?lhs \?rhs") proof- - {assume ?rhs then have "?lhs" by simp} + { assume ?rhs then have "?lhs" by simp } moreover - {assume h: ?lhs - {fix n have "b$n = c$n" - proof(induct n rule: nat_less_induct) - fix n assume H: "\mm {n} = {0 .. n}" using n1 by auto have d: "{0 .. n1} \ {n} = {}" using n1 by auto have seq: "(\i = 0..n1. b $ i * a ^ i $ n) = (\i = 0..n1. c $ i * a ^ i $ n)" apply (rule setsum_cong2) - using H n1 by auto + using H n1 apply auto + done have th0: "(b oo a) $n = (\i = 0..n1. c $ i * a ^ i $ n) + b$n * (a$1)^n" unfolding fps_compose_nth setsum_Un_disjoint[OF f d, unfolded eq] seq using startsby_zero_power_nth_same[OF a0] @@ -1657,7 +1736,8 @@ subsection {* Radicals *} declare setprod_cong[fundef_cong] -function radical :: "(nat \ 'a \ 'a) \ nat \ ('a::{field}) fps \ nat \ 'a" where +function radical :: "(nat \ 'a \ 'a) \ nat \ ('a::{field}) fps \ nat \ 'a" +where "radical r 0 a 0 = 1" | "radical r 0 a (Suc n) = 0" | "radical r (Suc k) a 0 = r (Suc k) (a$0)" @@ -1665,50 +1745,70 @@ (a$ Suc n - setsum (\xs. setprod (\j. radical r (Suc k) a (xs ! j)) {0..k}) {xs. xs \ natpermute (Suc n) (Suc k) \ Suc n \ set xs}) / (of_nat (Suc k) * (radical r (Suc k) a 0)^k)" -by pat_completeness auto + by pat_completeness auto termination radical proof let ?R = "measure (\(r, k, a, n). n)" { - show "wf ?R" by auto} - {fix r k a n xs i + show "wf ?R" by auto + next + fix r k a n xs i assume xs: "xs \ {xs \ natpermute (Suc n) (Suc k). Suc n \ set xs}" and i: "i \ {0..k}" - {assume c: "Suc n \ xs ! i" - from xs i have "xs !i \ Suc n" by (auto simp add: in_set_conv_nth natpermute_def) + { + assume c: "Suc n \ xs ! i" + from xs i have "xs !i \ Suc n" + by (auto simp add: in_set_conv_nth natpermute_def) with c have c': "Suc n < xs!i" by arith - have fths: "finite {0 ..< i}" "finite {i}" "finite {i+1.. ({i} \ {i+1 ..< Suc k}) = {}" "{i} \ {i+1..< Suc k} = {}" by auto - have eqs: "{0.. ({i} \ {i+1 ..< Suc k})" using i by auto - from xs have "Suc n = listsum xs" by (simp add: natpermute_def) + have fths: "finite {0 ..< i}" "finite {i}" "finite {i+1.. ({i} \ {i+1 ..< Suc k}) = {}" "{i} \ {i+1..< Suc k} = {}" + by auto + have eqs: "{0.. ({i} \ {i+1 ..< Suc k})" + using i by auto + from xs have "Suc n = listsum xs" + by (simp add: natpermute_def) also have "\ = setsum (nth xs) {0.. = xs!i + setsum (nth xs) {0.. ?R" - apply auto by (metis not_less)} - {fix r k a n - show "((r,Suc k, a, 0),r, Suc k, a, Suc n) \ ?R" by simp} + finally have False using c' by simp + } + then show "((r, Suc k, a, xs!i), r, Suc k, a, Suc n) \ ?R" + apply auto + apply (metis not_less) + done + next + fix r k a n + show "((r, Suc k, a, 0), r, Suc k, a, Suc n) \ ?R" by simp + } qed definition "fps_radical r n a = Abs_fps (radical r n a)" lemma fps_radical0[simp]: "fps_radical r 0 a = 1" - apply (auto simp add: fps_eq_iff fps_radical_def) by (case_tac n, auto) + apply (auto simp add: fps_eq_iff fps_radical_def) + apply (case_tac n) + apply auto + done lemma fps_radical_nth_0[simp]: "fps_radical r n a $ 0 = (if n=0 then 1 else r n (a$0))" - by (cases n, simp_all add: fps_radical_def) + by (cases n) (simp_all add: fps_radical_def) lemma fps_radical_power_nth[simp]: assumes r: "(r k (a$0)) ^ k = a$0" shows "fps_radical r k a ^ k $ 0 = (if k = 0 then 1 else a$0)" proof- - {assume "k=0" hence ?thesis by simp } + { + assume "k = 0" + hence ?thesis by simp + } moreover - {fix h assume h: "k = Suc h" + { + fix h + assume h: "k = Suc h" have eq1: "fps_radical r k a ^ k $ 0 = (\j\{0..h}. fps_radical r k a $ (replicate k 0) ! j)" unfolding fps_power_nth h by simp also have "\ = (\j\{0..h}. r k (a$0))" @@ -1716,35 +1816,42 @@ apply simp using h apply (subgoal_tac "replicate k (0::nat) ! x = 0") - by (auto intro: nth_replicate simp del: replicate.simps) - also have "\ = a$0" - using r by (simp add: h setprod_constant) + apply (auto intro: nth_replicate simp del: replicate.simps) + done + also have "\ = a$0" using r by (simp add: h setprod_constant) finally have ?thesis using h by simp} - ultimately show ?thesis by (cases k, auto) + ultimately show ?thesis by (cases k) auto qed -lemma natpermute_max_card: assumes n0: "n\0" - shows "card {xs \ natpermute n (k+1). n \ set xs} = k+1" +lemma natpermute_max_card: + assumes n0: "n\0" + shows "card {xs \ natpermute n (k+1). n \ set xs} = k + 1" unfolding natpermute_contain_maximal -proof- +proof - let ?A= "\i. {replicate (k + 1) 0[i := n]}" let ?K = "{0 ..k}" have fK: "finite ?K" by simp have fAK: "\i\?K. finite (?A i)" by auto have d: "\i\ ?K. \j\ ?K. i \ j \ {replicate (k + 1) 0[i := n]} \ {replicate (k + 1) 0[j := n]} = {}" - proof(clarify) - fix i j assume i: "i \ ?K" and j: "j\ ?K" and ij: "i\j" - {assume eq: "replicate (k+1) 0 [i:=n] = replicate (k+1) 0 [j:= n]" - have "(replicate (k+1) 0 [i:=n] ! i) = n" using i by (simp del: replicate.simps) + proof clarify + fix i j + assume i: "i \ ?K" and j: "j\ ?K" and ij: "i\j" + { + assume eq: "replicate (k+1) 0 [i:=n] = replicate (k+1) 0 [j:= n]" + have "(replicate (k+1) 0 [i:=n] ! i) = n" + using i by (simp del: replicate.simps) moreover - have "(replicate (k+1) 0 [j:=n] ! i) = 0" using i ij by (simp del: replicate.simps) - ultimately have False using eq n0 by (simp del: replicate.simps)} + have "(replicate (k+1) 0 [j:=n] ! i) = 0" + using i ij by (simp del: replicate.simps) + ultimately have False + using eq n0 by (simp del: replicate.simps) + } then show "{replicate (k + 1) 0[i := n]} \ {replicate (k + 1) 0[j := n]} = {}" by auto qed - from card_UN_disjoint[OF fK fAK d] - show "card (\i\{0..k}. {replicate (k + 1) 0[i := n]}) = k+1" by simp + from card_UN_disjoint[OF fK fAK d] show "card (\i\{0..k}. {replicate (k + 1) 0[i := n]}) = k+1" + by simp qed lemma power_radical: @@ -1931,7 +2038,7 @@ unfolding setsum_Un_disjoint[OF fths(2) fths(3) d(2)] by simp finally have False using c' by simp} - then have thn: "xs!i < n" by arith + then have thn: "xs!i < n" by presburger from h[rule_format, OF thn] show "a$(xs !i) = ?r$(xs!i)" . qed @@ -1956,7 +2063,8 @@ by (simp add: field_simps n1 th00 del: of_nat_Suc)} ultimately show "a$n = ?r $ n" by (cases n, auto) qed} - then have "a = ?r" by (simp add: fps_eq_iff)} + then have "a = ?r" by (simp add: fps_eq_iff) + } ultimately show ?thesis by blast qed @@ -2074,26 +2182,31 @@ have ra0': "r k (a$0) \ 0" using a0 ra0 k by auto have rb0': "r k (b$0) \ 0" using b0 rb0 k by auto - {assume ?rhs + { + assume ?rhs then have "?r (a/b) $ 0 = (?r a / ?r b)$0" by simp then have ?lhs using k a0 b0 rb0' - by (simp add: fps_divide_def fps_mult_nth fps_inverse_def divide_inverse) } + by (simp add: fps_divide_def fps_mult_nth fps_inverse_def divide_inverse) + } moreover - {assume h: ?lhs + { + assume h: ?lhs from a0 b0 have ab0[simp]: "(a/b)$0 = a$0 / b$0" by (simp add: fps_divide_def fps_mult_nth divide_inverse fps_inverse_def) have th0: "r k ((a/b)$0) ^ k = (a/b)$0" - by (simp add: h nonzero_power_divide[OF rb0'] ra0 rb0 del: k) + by (simp add: h nonzero_power_divide[OF rb0'] ra0 rb0) from a0 b0 ra0' rb0' kp h have th1: "r k ((a / b) $ 0) = (fps_radical r k a / fps_radical r k b) $ 0" - by (simp add: fps_divide_def fps_mult_nth fps_inverse_def divide_inverse del: k) + by (simp add: fps_divide_def fps_mult_nth fps_inverse_def divide_inverse) from a0 b0 ra0' rb0' kp have ab0': "(a / b) $ 0 \ 0" by (simp add: fps_divide_def fps_mult_nth fps_inverse_def nonzero_imp_inverse_nonzero) note tha[simp] = iffD1[OF power_radical[where r=r and k=h], OF a0 ra0[unfolded k], unfolded k[symmetric]] note thb[simp] = iffD1[OF power_radical[where r=r and k=h], OF b0 rb0[unfolded k], unfolded k[symmetric]] have th2: "(?r a / ?r b)^k = a/b" by (simp add: fps_divide_def power_mult_distrib fps_inverse_power[symmetric]) - from iffD1[OF radical_unique[where r=r and a="?r a / ?r b" and b="a/b" and k=h], symmetric, unfolded k[symmetric], OF th0 th1 ab0' th2] have ?rhs .} + from iffD1[OF radical_unique[where r=r and a="?r a / ?r b" and b="a/b" and k=h], symmetric, unfolded k[symmetric], OF th0 th1 ab0' th2] + have ?rhs . + } ultimately show ?thesis by blast qed @@ -2365,7 +2478,7 @@ let ?f = "%s. UNION {(0::nat)..s} (%i. {(i,s - i)})" have th0: "?KM = UNION {0..n} ?f" apply (simp add: set_eq_iff) - apply arith (* FIXME: VERY slow! *) + apply presburger (* FIXME: slow! *) done show "?l = ?r " unfolding th0 @@ -2419,7 +2532,7 @@ unfolding diff_minus fps_compose_uminus fps_compose_add_distrib .. lemma X_fps_compose:"X oo a = Abs_fps (\n. if n = 0 then (0::'a::comm_ring_1) else a$n)" - by (simp add: fps_eq_iff fps_compose_nth mult_delta_left setsum_delta power_Suc) + by (simp add: fps_eq_iff fps_compose_nth mult_delta_left setsum_delta) lemma fps_inverse_compose: assumes b0: "(b$0 :: 'a::field) = 0" and a0: "a$0 \ 0" @@ -2555,7 +2668,7 @@ let ?d = "fps_deriv a oo ?ia" let ?dia = "fps_deriv ?ia" have ia0: "?ia$0 = 0" by (simp add: fps_inv_def) - have th0: "?d$0 \ 0" using a1 by (simp add: fps_compose_nth fps_deriv_nth) + have th0: "?d$0 \ 0" using a1 by (simp add: fps_compose_nth) from fps_inv_right[OF a0 a1] have "?d * ?dia = 1" by (simp add: fps_compose_deriv[OF ia0, of a, symmetric] ) hence "inverse ?d * ?d * ?dia = inverse ?d * 1" by simp @@ -2646,25 +2759,32 @@ {assume d: ?lhs from d have th: "\n. a $ Suc n = c * a$n / of_nat (Suc n)" by (simp add: fps_deriv_def fps_eq_iff field_simps del: of_nat_Suc) - {fix n have "a$n = a$0 * c ^ n/ (of_nat (fact n))" + { + fix n + have "a$n = a$0 * c ^ n/ (of_nat (fact n))" apply (induct n) apply simp unfolding th using fact_gt_zero_nat apply (simp add: field_simps del: of_nat_Suc fact_Suc) apply (drule sym) - by (simp add: field_simps of_nat_mult power_Suc)} + apply (simp add: field_simps of_nat_mult) + done + } note th' = this have ?rhs by (auto simp add: fps_eq_iff fps_const_mult_left E_def intro : th')} -moreover -{assume h: ?rhs - have ?lhs - apply (subst h) - apply simp - apply (simp only: h[symmetric]) - by simp} -ultimately show ?thesis by blast + moreover + { + assume h: ?rhs + have ?lhs + apply (subst h) + apply simp + apply (simp only: h[symmetric]) + apply simp + done + } + ultimately show ?thesis by blast qed lemma E_add_mult: "E (a + b) = E (a::'a::field_char_0) * E b" (is "?l = ?r") @@ -2691,7 +2811,7 @@ qed lemma E_nth_deriv[simp]: "fps_nth_deriv n (E (a::'a::field_char_0)) = (fps_const a)^n * (E a)" - by (induct n) (auto simp add: power_Suc) + by (induct n) auto lemma X_compose_E[simp]: "X oo E (a::'a::{field}) = E a - 1" by (simp add: fps_eq_iff X_fps_compose) @@ -2724,7 +2844,7 @@ qed lemma E_power_mult: "(E (c::'a::field_char_0))^n = E (of_nat n * c)" - by (induct n) (auto simp add: field_simps E_add_mult power_Suc) + by (induct n) (auto simp add: field_simps E_add_mult) lemma radical_E: assumes r: "r (Suc k) 1 = 1" @@ -2741,19 +2861,21 @@ show ?thesis by auto qed -lemma Ec_E1_eq: - "E (1::'a::{field_char_0}) oo (fps_const c * X) = E c" +lemma Ec_E1_eq: "E (1::'a::{field_char_0}) oo (fps_const c * X) = E c" apply (auto simp add: fps_eq_iff E_def fps_compose_def power_mult_distrib) - by (simp add: cond_value_iff cond_application_beta setsum_delta' cong del: if_weak_cong) + apply (simp add: cond_value_iff cond_application_beta setsum_delta' cong del: if_weak_cong) + done text{* The generalized binomial theorem as a consequence of @{thm E_add_mult} *} lemma gbinomial_theorem: - "((a::'a::{field_char_0, field_inverse_zero})+b) ^ n = (\k=0..n. of_nat (n choose k) * a^k * b^(n-k))" -proof- + "((a::'a::{field_char_0, field_inverse_zero})+b) ^ n = + (\k=0..n. of_nat (n choose k) * a^k * b^(n-k))" +proof - from E_add_mult[of a b] have "(E (a + b)) $ n = (E a * E b)$n" by simp - then have "(a + b) ^ n = (\i\nat = 0\nat..n. a ^ i * b ^ (n - i) * (of_nat (fact n) / of_nat (fact i * fact (n - i))))" + then have "(a + b) ^ n = + (\i\nat = 0\nat..n. a ^ i * b ^ (n - i) * (of_nat (fact n) / of_nat (fact i * fact (n - i))))" by (simp add: field_simps fps_mult_nth of_nat_mult[symmetric] setsum_right_distrib) then show ?thesis apply simp @@ -2775,8 +2897,8 @@ "Abs_fps(%n. if n=0 then (v::'a::ring_1) else f n) = fps_const v + X * Abs_fps (%n. f (Suc n))" by (auto simp add: fps_eq_iff) -definition L:: "'a::{field_char_0} \ 'a fps" where - "L c \ fps_const (1/c) * Abs_fps (\n. if n = 0 then 0 else (- 1) ^ (n - 1) / of_nat n)" +definition L :: "'a::field_char_0 \ 'a fps" + where "L c = fps_const (1/c) * Abs_fps (\n. if n = 0 then 0 else (- 1) ^ (n - 1) / of_nat n)" lemma fps_deriv_L: "fps_deriv (L c) = fps_const (1/c) * inverse (1 + X)" unfolding inverse_one_plus_X @@ -3005,7 +3127,7 @@ unfolding m1nk unfolding m h pochhammer_Suc_setprod - apply (simp add: field_simps del: fact_Suc id_def minus_one) + apply (simp add: field_simps del: fact_Suc minus_one) unfolding fact_altdef_nat id_def unfolding of_nat_setprod unfolding setprod_timesf[symmetric] @@ -3108,54 +3230,57 @@ (is "?lhs = ?rhs") proof (rule fps_ext) fix n::nat - {assume en: "even n" - have "?lhs$n = of_nat (n+1) * (fps_sin c $ (n+1))" by simp - also have "\ = of_nat (n+1) * ((- 1)^(n div 2) * c^Suc n / of_nat (fact (Suc n)))" - using en by (simp add: fps_sin_def) - also have "\ = (- 1)^(n div 2) * c^Suc n * (of_nat (n+1) / (of_nat (Suc n) * of_nat (fact n)))" - unfolding fact_Suc of_nat_mult - by (simp add: field_simps del: of_nat_add of_nat_Suc) - also have "\ = (- 1)^(n div 2) *c^Suc n / of_nat (fact n)" - by (simp add: field_simps del: of_nat_add of_nat_Suc) - finally have "?lhs $n = ?rhs$n" using en - by (simp add: fps_cos_def field_simps power_Suc )} - then show "?lhs $ n = ?rhs $ n" - by (cases "even n", simp_all add: fps_deriv_def fps_sin_def fps_cos_def) + { + assume en: "even n" + have "?lhs$n = of_nat (n+1) * (fps_sin c $ (n+1))" by simp + also have "\ = of_nat (n+1) * ((- 1)^(n div 2) * c^Suc n / of_nat (fact (Suc n)))" + using en by (simp add: fps_sin_def) + also have "\ = (- 1)^(n div 2) * c^Suc n * (of_nat (n+1) / (of_nat (Suc n) * of_nat (fact n)))" + unfolding fact_Suc of_nat_mult + by (simp add: field_simps del: of_nat_add of_nat_Suc) + also have "\ = (- 1)^(n div 2) *c^Suc n / of_nat (fact n)" + by (simp add: field_simps del: of_nat_add of_nat_Suc) + finally have "?lhs $n = ?rhs$n" using en + by (simp add: fps_cos_def field_simps) + } + then show "?lhs $ n = ?rhs $ n" + by (cases "even n", simp_all add: fps_deriv_def fps_sin_def fps_cos_def) qed -lemma fps_cos_deriv: - "fps_deriv (fps_cos c) = fps_const (- c)* (fps_sin c)" +lemma fps_cos_deriv: "fps_deriv (fps_cos c) = fps_const (- c)* (fps_sin c)" (is "?lhs = ?rhs") proof (rule fps_ext) - have th0: "\n. - ((- 1::'a) ^ n) = (- 1)^Suc n" by (simp add: power_Suc) + have th0: "\n. - ((- 1::'a) ^ n) = (- 1)^Suc n" by simp have th1: "\n. odd n \ Suc ((n - 1) div 2) = Suc n div 2" by (case_tac n, simp_all) fix n::nat - {assume en: "odd n" - from en have n0: "n \0 " by presburger - have "?lhs$n = of_nat (n+1) * (fps_cos c $ (n+1))" by simp - also have "\ = of_nat (n+1) * ((- 1)^((n + 1) div 2) * c^Suc n / of_nat (fact (Suc n)))" - using en by (simp add: fps_cos_def) - also have "\ = (- 1)^((n + 1) div 2)*c^Suc n * (of_nat (n+1) / (of_nat (Suc n) * of_nat (fact n)))" - unfolding fact_Suc of_nat_mult - by (simp add: field_simps del: of_nat_add of_nat_Suc) - also have "\ = (- 1)^((n + 1) div 2) * c^Suc n / of_nat (fact n)" - by (simp add: field_simps del: of_nat_add of_nat_Suc) - also have "\ = (- ((- 1)^((n - 1) div 2))) * c^Suc n / of_nat (fact n)" - unfolding th0 unfolding th1[OF en] by simp - finally have "?lhs $n = ?rhs$n" using en - by (simp add: fps_sin_def field_simps power_Suc)} - then show "?lhs $ n = ?rhs $ n" - by (cases "even n", simp_all add: fps_deriv_def fps_sin_def - fps_cos_def) + { + assume en: "odd n" + from en have n0: "n \0 " by presburger + have "?lhs$n = of_nat (n+1) * (fps_cos c $ (n+1))" by simp + also have "\ = of_nat (n+1) * ((- 1)^((n + 1) div 2) * c^Suc n / of_nat (fact (Suc n)))" + using en by (simp add: fps_cos_def) + also have "\ = (- 1)^((n + 1) div 2)*c^Suc n * (of_nat (n+1) / (of_nat (Suc n) * of_nat (fact n)))" + unfolding fact_Suc of_nat_mult + by (simp add: field_simps del: of_nat_add of_nat_Suc) + also have "\ = (- 1)^((n + 1) div 2) * c^Suc n / of_nat (fact n)" + by (simp add: field_simps del: of_nat_add of_nat_Suc) + also have "\ = (- ((- 1)^((n - 1) div 2))) * c^Suc n / of_nat (fact n)" + unfolding th0 unfolding th1[OF en] by simp + finally have "?lhs $n = ?rhs$n" using en + by (simp add: fps_sin_def field_simps) + } + then show "?lhs $ n = ?rhs $ n" + by (cases "even n") (simp_all add: fps_deriv_def fps_sin_def fps_cos_def) qed lemma fps_sin_cos_sum_of_squares: "fps_cos c ^ 2 + fps_sin c ^ 2 = 1" (is "?lhs = 1") proof- have "fps_deriv ?lhs = 0" - apply (simp add: fps_deriv_power fps_sin_deriv fps_cos_deriv power_Suc) - by (simp add: field_simps fps_const_neg[symmetric] del: fps_const_neg) + apply (simp add: fps_deriv_power fps_sin_deriv fps_cos_deriv) + apply (simp add: field_simps fps_const_neg[symmetric] del: fps_const_neg) + done then have "?lhs = fps_const (?lhs $ 0)" unfolding fps_deriv_eq_0_iff . also have "\ = 1" @@ -3191,78 +3316,77 @@ lemma fps_cos_nth_add_2: "fps_cos c $ (n + 2) = - (c * c * fps_cos c $ n / (of_nat(n+1) * of_nat(n+2)))" -unfolding fps_cos_def -apply (simp add: divide_eq_iff eq_divide_iff del: of_nat_Suc fact_Suc) -apply (simp add: of_nat_mult del: of_nat_Suc mult_Suc) -done - -lemma nat_induct2: - "\P 0; P 1; \n. P n \ P (n + 2)\ \ P (n::nat)" -unfolding One_nat_def numeral_2_eq_2 -apply (induct n rule: nat_less_induct) -apply (case_tac n, simp) -apply (rename_tac m, case_tac m, simp) -apply (rename_tac k, case_tac k, simp_all) -done + unfolding fps_cos_def + apply (simp add: divide_eq_iff eq_divide_iff del: of_nat_Suc fact_Suc) + apply (simp add: of_nat_mult del: of_nat_Suc mult_Suc) + done + +lemma nat_induct2: "P 0 \ P 1 \ (\n. P n \ P (n + 2)) \ P (n::nat)" + unfolding One_nat_def numeral_2_eq_2 + apply (induct n rule: nat_less_induct) + apply (case_tac n, simp) + apply (rename_tac m, case_tac m, simp) + apply (rename_tac k, case_tac k, simp_all) + done lemma nat_add_1_add_1: "(n::nat) + 1 + 1 = n + 2" -by simp + by simp lemma eq_fps_sin: - assumes 0: "a $ 0 = 0" and 1: "a $ 1 = c" - and 2: "fps_deriv (fps_deriv a) = - (fps_const c * fps_const c * a)" + assumes 0: "a $ 0 = 0" + and 1: "a $ 1 = c" + and 2: "fps_deriv (fps_deriv a) = - (fps_const c * fps_const c * a)" shows "a = fps_sin c" -apply (rule fps_ext) -apply (induct_tac n rule: nat_induct2) -apply (simp add: fps_sin_nth_0 0) -apply (simp add: fps_sin_nth_1 1 del: One_nat_def) -apply (rename_tac m, cut_tac f="\a. a $ m" in arg_cong [OF 2]) -apply (simp add: nat_add_1_add_1 fps_sin_nth_add_2 - del: One_nat_def of_nat_Suc of_nat_add add_2_eq_Suc') -apply (subst minus_divide_left) -apply (subst eq_divide_iff) -apply (simp del: of_nat_add of_nat_Suc) -apply (simp only: mult_ac) -done + apply (rule fps_ext) + apply (induct_tac n rule: nat_induct2) + apply (simp add: 0) + apply (simp add: 1 del: One_nat_def) + apply (rename_tac m, cut_tac f="\a. a $ m" in arg_cong [OF 2]) + apply (simp add: nat_add_1_add_1 fps_sin_nth_add_2 + del: One_nat_def of_nat_Suc of_nat_add add_2_eq_Suc') + apply (subst minus_divide_left) + apply (subst eq_divide_iff) + apply (simp del: of_nat_add of_nat_Suc) + apply (simp only: mult_ac) + done lemma eq_fps_cos: - assumes 0: "a $ 0 = 1" and 1: "a $ 1 = 0" - and 2: "fps_deriv (fps_deriv a) = - (fps_const c * fps_const c * a)" + assumes 0: "a $ 0 = 1" + and 1: "a $ 1 = 0" + and 2: "fps_deriv (fps_deriv a) = - (fps_const c * fps_const c * a)" shows "a = fps_cos c" -apply (rule fps_ext) -apply (induct_tac n rule: nat_induct2) -apply (simp add: fps_cos_nth_0 0) -apply (simp add: fps_cos_nth_1 1 del: One_nat_def) -apply (rename_tac m, cut_tac f="\a. a $ m" in arg_cong [OF 2]) -apply (simp add: nat_add_1_add_1 fps_cos_nth_add_2 - del: One_nat_def of_nat_Suc of_nat_add add_2_eq_Suc') -apply (subst minus_divide_left) -apply (subst eq_divide_iff) -apply (simp del: of_nat_add of_nat_Suc) -apply (simp only: mult_ac) -done + apply (rule fps_ext) + apply (induct_tac n rule: nat_induct2) + apply (simp add: 0) + apply (simp add: 1 del: One_nat_def) + apply (rename_tac m, cut_tac f="\a. a $ m" in arg_cong [OF 2]) + apply (simp add: nat_add_1_add_1 fps_cos_nth_add_2 + del: One_nat_def of_nat_Suc of_nat_add add_2_eq_Suc') + apply (subst minus_divide_left) + apply (subst eq_divide_iff) + apply (simp del: of_nat_add of_nat_Suc) + apply (simp only: mult_ac) + done lemma mult_nth_0 [simp]: "(a * b) $ 0 = a $ 0 * b $ 0" -by (simp add: fps_mult_nth) + by (simp add: fps_mult_nth) lemma mult_nth_1 [simp]: "(a * b) $ 1 = a $ 0 * b $ 1 + a $ 1 * b $ 0" -by (simp add: fps_mult_nth) - -lemma fps_sin_add: - "fps_sin (a + b) = fps_sin a * fps_cos b + fps_cos a * fps_sin b" -apply (rule eq_fps_sin [symmetric], simp, simp del: One_nat_def) -apply (simp del: fps_const_neg fps_const_add fps_const_mult - add: fps_const_add [symmetric] fps_const_neg [symmetric] - fps_sin_deriv fps_cos_deriv algebra_simps) -done - -lemma fps_cos_add: - "fps_cos (a + b) = fps_cos a * fps_cos b - fps_sin a * fps_sin b" -apply (rule eq_fps_cos [symmetric], simp, simp del: One_nat_def) -apply (simp del: fps_const_neg fps_const_add fps_const_mult - add: fps_const_add [symmetric] fps_const_neg [symmetric] - fps_sin_deriv fps_cos_deriv algebra_simps) -done + by (simp add: fps_mult_nth) + +lemma fps_sin_add: "fps_sin (a + b) = fps_sin a * fps_cos b + fps_cos a * fps_sin b" + apply (rule eq_fps_sin [symmetric], simp, simp del: One_nat_def) + apply (simp del: fps_const_neg fps_const_add fps_const_mult + add: fps_const_add [symmetric] fps_const_neg [symmetric] + fps_sin_deriv fps_cos_deriv algebra_simps) + done + +lemma fps_cos_add: "fps_cos (a + b) = fps_cos a * fps_cos b - fps_sin a * fps_sin b" + apply (rule eq_fps_cos [symmetric], simp, simp del: One_nat_def) + apply (simp del: fps_const_neg fps_const_add fps_const_mult + add: fps_const_add [symmetric] fps_const_neg [symmetric] + fps_sin_deriv fps_cos_deriv algebra_simps) + done lemma fps_sin_even: "fps_sin (- c) = - fps_sin c" by (auto simp add: fps_eq_iff fps_sin_def) @@ -3273,40 +3397,44 @@ definition "fps_tan c = fps_sin c / fps_cos c" lemma fps_tan_deriv: "fps_deriv(fps_tan c) = fps_const c/ (fps_cos c ^ 2)" -proof- +proof - have th0: "fps_cos c $ 0 \ 0" by (simp add: fps_cos_def) show ?thesis using fps_sin_cos_sum_of_squares[of c] - apply (simp add: fps_tan_def fps_divide_deriv[OF th0] fps_sin_deriv fps_cos_deriv add: fps_const_neg[symmetric] field_simps power2_eq_square del: fps_const_neg) + apply (simp add: fps_tan_def fps_divide_deriv[OF th0] fps_sin_deriv fps_cos_deriv + fps_const_neg[symmetric] field_simps power2_eq_square del: fps_const_neg) unfolding distrib_left[symmetric] - by simp + apply simp + done qed text {* Connection to E c over the complex numbers --- Euler and De Moivre*} -lemma Eii_sin_cos: - "E (ii * c) = fps_cos c + fps_const ii * fps_sin c " +lemma Eii_sin_cos: "E (ii * c) = fps_cos c + fps_const ii * fps_sin c " (is "?l = ?r") -proof- - {fix n::nat - {assume en: "even n" - from en obtain m where m: "n = 2*m" +proof - + { fix n :: nat + { + assume en: "even n" + from en obtain m where m: "n = 2 * m" unfolding even_mult_two_ex by blast have "?l $n = ?r$n" - by (simp add: m fps_sin_def fps_cos_def power_mult_distrib - power_mult power_minus)} + by (simp add: m fps_sin_def fps_cos_def power_mult_distrib power_mult power_minus) + } moreover - {assume on: "odd n" + { + assume on: "odd n" from on obtain m where m: "n = 2*m + 1" unfolding odd_nat_equiv_def2 by (auto simp add: mult_2) have "?l $n = ?r$n" by (simp add: m fps_sin_def fps_cos_def power_mult_distrib - power_mult power_minus)} - ultimately have "?l $n = ?r$n" by blast} - then show ?thesis by (simp add: fps_eq_iff) + power_mult power_minus) + } + ultimately have "?l $n = ?r$n" by blast + } then show ?thesis by (simp add: fps_eq_iff) qed -lemma E_minus_ii_sin_cos: "E (- (ii * c)) = fps_cos c - fps_const ii * fps_sin c " +lemma E_minus_ii_sin_cos: "E (- (ii * c)) = fps_cos c - fps_const ii * fps_sin c" unfolding minus_mult_right Eii_sin_cos by (simp add: fps_sin_even fps_cos_odd) lemma fps_const_minus: "fps_const (c::'a::group_add) - fps_const d = fps_const (c - d)" @@ -3315,43 +3443,44 @@ lemma fps_numeral_fps_const: "numeral i = fps_const (numeral i :: 'a:: {comm_ring_1})" by (fact numeral_fps_const) (* FIXME: duplicate *) -lemma fps_cos_Eii: - "fps_cos c = (E (ii * c) + E (- ii * c)) / fps_const 2" -proof- +lemma fps_cos_Eii: "fps_cos c = (E (ii * c) + E (- ii * c)) / fps_const 2" +proof - have th: "fps_cos c + fps_cos c = fps_cos c * fps_const 2" by (simp add: numeral_fps_const) show ?thesis unfolding Eii_sin_cos minus_mult_commute - by (simp add: fps_sin_even fps_cos_odd numeral_fps_const - fps_divide_def fps_const_inverse th) + by (simp add: fps_sin_even fps_cos_odd numeral_fps_const fps_divide_def fps_const_inverse th) qed -lemma fps_sin_Eii: - "fps_sin c = (E (ii * c) - E (- ii * c)) / fps_const (2*ii)" -proof- +lemma fps_sin_Eii: "fps_sin c = (E (ii * c) - E (- ii * c)) / fps_const (2*ii)" +proof - have th: "fps_const \ * fps_sin c + fps_const \ * fps_sin c = fps_sin c * fps_const (2 * ii)" by (simp add: fps_eq_iff numeral_fps_const) show ?thesis - unfolding Eii_sin_cos minus_mult_commute - by (simp add: fps_sin_even fps_cos_odd fps_divide_def fps_const_inverse th) + unfolding Eii_sin_cos minus_mult_commute + by (simp add: fps_sin_even fps_cos_odd fps_divide_def fps_const_inverse th) qed lemma fps_tan_Eii: "fps_tan c = (E (ii * c) - E (- ii * c)) / (fps_const ii * (E (ii * c) + E (- ii * c)))" unfolding fps_tan_def fps_sin_Eii fps_cos_Eii mult_minus_left E_neg apply (simp add: fps_divide_def fps_inverse_mult fps_const_mult[symmetric] fps_const_inverse del: fps_const_mult) - by simp + apply simp + done lemma fps_demoivre: "(fps_cos a + fps_const ii * fps_sin a)^n = fps_cos (of_nat n * a) + fps_const ii * fps_sin (of_nat n * a)" unfolding Eii_sin_cos[symmetric] E_power_mult by (simp add: mult_ac) + subsection {* Hypergeometric series *} - -definition "F as bs (c::'a::{field_char_0, field_inverse_zero}) = Abs_fps (%n. (foldl (%r a. r* pochhammer a n) 1 as * c^n)/ (foldl (%r b. r * pochhammer b n) 1 bs * of_nat (fact n)))" - -lemma F_nth[simp]: "F as bs c $ n = (foldl (%r a. r* pochhammer a n) 1 as * c^n)/ (foldl (%r b. r * pochhammer b n) 1 bs * of_nat (fact n))" +definition "F as bs (c::'a::{field_char_0, field_inverse_zero}) = + Abs_fps (%n. (foldl (%r a. r* pochhammer a n) 1 as * c^n)/ (foldl (%r b. r * pochhammer b n) 1 bs * of_nat (fact n)))" + +lemma F_nth[simp]: "F as bs c $ n = + (foldl (\r a. r* pochhammer a n) 1 as * c^n) / + (foldl (\r b. r * pochhammer b n) 1 bs * of_nat (fact n))" by (simp add: F_def) lemma foldl_mult_start: @@ -3369,7 +3498,7 @@ by (simp add: fps_eq_iff) lemma F_1_0[simp]: "F [1] [] c = 1/(1 - fps_const c * X)" -proof- +proof - let ?a = "(Abs_fps (\n. 1)) oo (fps_const c * X)" have th0: "(fps_const c * X) $ 0 = 0" by simp show ?thesis unfolding gp[OF th0, symmetric] @@ -3387,7 +3516,8 @@ apply auto done -lemma foldl_prod_prod: "foldl (%(r::'b::comm_ring_1) (x::'a::comm_ring_1). r * f x) v as * foldl (%r x. r * g x) w as = foldl (%r x. r * f x * g x) (v*w) as" +lemma foldl_prod_prod: "foldl (%(r::'b::comm_ring_1) (x::'a::comm_ring_1). r * f x) v as * foldl (%r x. r * g x) w as = + foldl (%r x. r * f x * g x) (v*w) as" by (induct as arbitrary: v w) (auto simp add: algebra_simps) @@ -3395,7 +3525,8 @@ apply (simp del: of_nat_Suc of_nat_add fact_Suc) apply (simp add: foldl_mult_start del: fact_Suc of_nat_Suc) unfolding foldl_prod_prod[unfolded foldl_mult_start] pochhammer_Suc - by (simp add: algebra_simps of_nat_mult) + apply (simp add: algebra_simps of_nat_mult) + done lemma XD_nth[simp]: "XD a $ n = (if n=0 then 0 else of_nat n * a$n)" by (simp add: XD_def) @@ -3408,50 +3539,51 @@ lemma XDp_nth[simp]: "XDp c a $ n = (c + of_nat n) * a$n" by (simp add: XDp_def algebra_simps) -lemma XDp_commute: - shows "XDp b o XDp (c::'a::comm_ring_1) = XDp c o XDp b" +lemma XDp_commute: "XDp b o XDp (c::'a::comm_ring_1) = XDp c o XDp b" by (auto simp add: XDp_def fun_eq_iff fps_eq_iff algebra_simps) -lemma XDp0[simp]: "XDp 0 = XD" +lemma XDp0 [simp]: "XDp 0 = XD" by (simp add: fun_eq_iff fps_eq_iff) -lemma XDp_fps_integral[simp]:"XDp 0 (fps_integral a c) = X * a" +lemma XDp_fps_integral [simp]: "XDp 0 (fps_integral a c) = X * a" by (simp add: fps_eq_iff fps_integral_def) lemma F_minus_nat: - "F [- of_nat n] [- of_nat (n + m)] (c::'a::{field_char_0, field_inverse_zero}) $ k = (if k <= n then pochhammer (- of_nat n) k * c ^ k / - (pochhammer (- of_nat (n + m)) k * of_nat (fact k)) else 0)" - "F [- of_nat m] [- of_nat (m + n)] (c::'a::{field_char_0, field_inverse_zero}) $ k = (if k <= m then pochhammer (- of_nat m) k * c ^ k / - (pochhammer (- of_nat (m + n)) k * of_nat (fact k)) else 0)" + "F [- of_nat n] [- of_nat (n + m)] (c::'a::{field_char_0, field_inverse_zero}) $ k = + (if k <= n then + pochhammer (- of_nat n) k * c ^ k / (pochhammer (- of_nat (n + m)) k * of_nat (fact k)) + else 0)" + "F [- of_nat m] [- of_nat (m + n)] (c::'a::{field_char_0, field_inverse_zero}) $ k = + (if k <= m then + pochhammer (- of_nat m) k * c ^ k / (pochhammer (- of_nat (m + n)) k * of_nat (fact k)) + else 0)" by (auto simp add: pochhammer_eq_0_iff) lemma setsum_eq_if: "setsum f {(n::nat) .. m} = (if m < n then 0 else f n + setsum f {n+1 .. m})" apply simp apply (subst setsum_insert[symmetric]) - by (auto simp add: not_less setsum_head_Suc) - -lemma pochhammer_rec_if: - "pochhammer a n = (if n = 0 then 1 else a * pochhammer (a + 1) (n - 1))" - by (cases n, simp_all add: pochhammer_rec) - -lemma XDp_foldr_nth[simp]: "foldr (%c r. XDp c o r) cs (%c. XDp c a) c0 $ n = + apply (auto simp add: not_less setsum_head_Suc) + done + +lemma pochhammer_rec_if: "pochhammer a n = (if n = 0 then 1 else a * pochhammer (a + 1) (n - 1))" + by (cases n) (simp_all add: pochhammer_rec) + +lemma XDp_foldr_nth [simp]: "foldr (%c r. XDp c o r) cs (%c. XDp c a) c0 $ n = foldr (%c r. (c + of_nat n) * r) cs (c0 + of_nat n) * a$n" by (induct cs arbitrary: c0) (auto simp add: algebra_simps) lemma genric_XDp_foldr_nth: - assumes - f: "ALL n c a. f c a $ n = (of_nat n + k c) * a$n" - + assumes f: "ALL n c a. f c a $ n = (of_nat n + k c) * a$n" shows "foldr (%c r. f c o r) cs (%c. g c a) c0 $ n = - foldr (%c r. (k c + of_nat n) * r) cs (g c0 a $ n)" + foldr (%c r. (k c + of_nat n) * r) cs (g c0 a $ n)" by (induct cs arbitrary: c0) (auto simp add: algebra_simps f) lemma dist_less_imp_nth_equal: assumes "dist f g < inverse (2 ^ i)" - assumes "j \ i" + and"j \ i" shows "f $ j = g $ j" -proof cases - assume "f \ g" +proof (cases "f = g") + case False hence "\n. f $ n \ g $ n" by (simp add: fps_eq_iff) with assms have "i < The (leastP (\n. f $ n \ g $ n))" by (simp add: split_if_asm dist_fps_def) @@ -3461,13 +3593,16 @@ moreover hence "\m. m < n \ f$m = g$m" "f$n \ g$n" by (auto simp add: leastP_def setge_def) ultimately show ?thesis using `j \ i` by simp -qed simp +next + case True + then show ?thesis by simp +qed lemma nth_equal_imp_dist_less: assumes "\j. j \ i \ f $ j = g $ j" shows "dist f g < inverse (2 ^ i)" -proof cases - assume "f \ g" +proof (cases "f = g") + case False hence "\n. f $ n \ g $ n" by (simp add: fps_eq_iff) with assms have "dist f g = inverse (2 ^ (The (leastP (\n. f $ n \ g $ n))))" by (simp add: split_if_asm dist_fps_def) @@ -3477,10 +3612,12 @@ with assms have "i < The (leastP (\n. f $ n \ g $ n))" by (metis (full_types) leastPD1 not_le) ultimately show ?thesis by simp -qed simp - -lemma dist_less_eq_nth_equal: - shows "dist f g < inverse (2 ^ i) \ (\j \ i. f $ j = g $ j)" +next + case True + then show ?thesis by simp +qed + +lemma dist_less_eq_nth_equal: "dist f g < inverse (2 ^ i) \ (\j \ i. f $ j = g $ j)" using dist_less_imp_nth_equal nth_equal_imp_dist_less by blast instance fps :: (comm_ring_1) complete_space @@ -3504,12 +3641,15 @@ with LIMSEQ_inverse_realpow_zero[of 2, simplified, simplified filterlim_iff, THEN spec, of "\x. x < e"] have "eventually (\i. inverse (2 ^ i) < e) sequentially" - by safe (auto simp: eventually_nhds) + apply safe + apply (auto simp: eventually_nhds) + done then obtain i where "inverse (2 ^ i) < e" by (auto simp: eventually_sequentially) have "eventually (\x. M i \ x) sequentially" by (auto simp: eventually_sequentially) thus "eventually (\x. dist (X x) (Abs_fps (\i. X (M i) $ i)) < e) sequentially" proof eventually_elim - fix x assume "M i \ x" + fix x + assume "M i \ x" moreover have "\j. j \ i \ X (M i) $ j = X (M j) $ j" using M by (metis nat_le_linear)