--- a/src/HOL/IsaMakefile Thu Jul 23 22:20:37 2009 +0200
+++ b/src/HOL/IsaMakefile Thu Jul 23 23:15:45 2009 +0200
@@ -887,8 +887,7 @@
ex/Codegenerator_Pretty_Test.thy ex/Coherent.thy \
ex/Commutative_RingEx.thy ex/Commutative_Ring_Complete.thy \
ex/Efficient_Nat_examples.thy \
- ex/Eval_Examples.thy \
- ex/Formal_Power_Series_Examples.thy ex/Fundefs.thy \
+ ex/Eval_Examples.thy ex/Fundefs.thy \
ex/Groebner_Examples.thy ex/Guess.thy ex/HarmonicSeries.thy \
ex/Hebrew.thy ex/Hex_Bin_Examples.thy ex/Higher_Order_Logic.thy \
ex/Hilbert_Classical.thy \
--- a/src/HOL/Library/Binomial.thy Thu Jul 23 22:20:37 2009 +0200
+++ b/src/HOL/Library/Binomial.thy Thu Jul 23 23:15:45 2009 +0200
@@ -282,6 +282,56 @@
pochhammer_of_nat_eq_0_lemma'[of k n, where ?'a = 'a]
by (auto simp add: not_le[symmetric])
+
+lemma pochhammer_eq_0_iff:
+ "pochhammer a n = (0::'a::field_char_0) \<longleftrightarrow> (EX k < n . a = - of_nat k) "
+ apply (auto simp add: pochhammer_of_nat_eq_0_iff)
+ apply (cases n, auto simp add: pochhammer_def algebra_simps group_add_class.eq_neg_iff_add_eq_0)
+ apply (rule_tac x=x in exI)
+ apply auto
+ done
+
+
+lemma pochhammer_eq_0_mono:
+ "pochhammer a n = (0::'a::field_char_0) \<Longrightarrow> m \<ge> n \<Longrightarrow> pochhammer a m = 0"
+ unfolding pochhammer_eq_0_iff by auto
+
+lemma pochhammer_neq_0_mono:
+ "pochhammer a m \<noteq> (0::'a::field_char_0) \<Longrightarrow> m \<ge> n \<Longrightarrow> pochhammer a n \<noteq> 0"
+ unfolding pochhammer_eq_0_iff by auto
+
+lemma pochhammer_minus:
+ assumes kn: "k \<le> n"
+ shows "pochhammer (- b) k = ((- 1) ^ k :: 'a::comm_ring_1) * pochhammer (b - of_nat k + 1) k"
+proof-
+ {assume k0: "k = 0" then have ?thesis by simp}
+ moreover
+ {fix h assume h: "k = Suc h"
+ have eq: "((- 1) ^ Suc h :: 'a) = setprod (%i. - 1) {0 .. h}"
+ using setprod_constant[where A="{0 .. h}" and y="- 1 :: 'a"]
+ by auto
+ have ?thesis
+ unfolding h h pochhammer_Suc_setprod eq setprod_timesf[symmetric]
+ apply (rule strong_setprod_reindex_cong[where f = "%i. h - i"])
+ apply (auto simp add: inj_on_def image_def h )
+ apply (rule_tac x="h - x" in bexI)
+ by (auto simp add: expand_fun_eq h of_nat_diff)}
+ ultimately show ?thesis by (cases k, auto)
+qed
+
+lemma pochhammer_minus':
+ assumes kn: "k \<le> n"
+ shows "pochhammer (b - of_nat k + 1) k = ((- 1) ^ k :: 'a::comm_ring_1) * pochhammer (- b) k"
+ unfolding pochhammer_minus[OF kn, where b=b]
+ unfolding mult_assoc[symmetric]
+ unfolding power_add[symmetric]
+ apply simp
+ done
+
+lemma pochhammer_same: "pochhammer (- of_nat n) n = ((- 1) ^ n :: 'a::comm_ring_1) * of_nat (fact n)"
+ unfolding pochhammer_minus[OF le_refl[of n]]
+ by (simp add: of_nat_diff pochhammer_fact)
+
subsection{* Generalized binomial coefficients *}
definition gbinomial :: "'a::field_char_0 \<Rightarrow> nat \<Rightarrow> 'a" (infixl "gchoose" 65)
@@ -453,4 +503,14 @@
ultimately show ?thesis by (cases k, auto)
qed
+
+lemma binomial_symmetric: assumes kn: "k \<le> n"
+ shows "n choose k = n choose (n - k)"
+proof-
+ from kn have kn': "n - k \<le> n" by arith
+ from binomial_fact_lemma[OF kn] binomial_fact_lemma[OF kn']
+ have "fact k * fact (n - k) * (n choose k) = fact (n - k) * fact (n - (n - k)) * (n choose (n - k))" by simp
+ then show ?thesis using kn by simp
+qed
+
end
--- a/src/HOL/Library/Formal_Power_Series.thy Thu Jul 23 22:20:37 2009 +0200
+++ b/src/HOL/Library/Formal_Power_Series.thy Thu Jul 23 23:15:45 2009 +0200
@@ -5,7 +5,7 @@
header{* A formalization of formal power series *}
theory Formal_Power_Series
-imports Complex_Main
+imports Complex_Main Binomial
begin
@@ -469,7 +469,6 @@
lemma dist_fps_sym: "dist (a::'a fps) b = dist b a"
apply (auto simp add: dist_fps_def)
- thm cong[OF refl]
apply (rule cong[OF refl, where x="(\<lambda>n\<Colon>nat. a $ n \<noteq> b $ n)"])
apply (rule ext)
by auto
@@ -2333,7 +2332,6 @@
from a0 have ia0: "?ia $ 0 \<noteq> 0" by (simp )
from a0 have ab0: "?ab $ 0 \<noteq> 0" by (simp add: fps_compose_def)
-thm inverse_mult_eq_1[OF ab0]
have "(?ia oo b) * (a oo b) = 1"
unfolding fps_compose_mult_distrib[OF b0, symmetric]
unfolding inverse_mult_eq_1[OF a0]
@@ -2606,7 +2604,8 @@
lemma E_power_mult: "(E (c::'a::field_char_0))^n = E (of_nat n * c)"
by (induct n, auto simp add: ring_simps E_add_mult power_Suc)
-lemma assumes r: "r (Suc k) 1 = 1"
+lemma radical_E:
+ assumes r: "r (Suc k) 1 = 1"
shows "fps_radical r (Suc k) (E (c::'a::{field_char_0})) = E (c / of_nat (Suc k))"
proof-
let ?ck = "(c / of_nat (Suc k))"
@@ -2625,6 +2624,29 @@
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)
+text{* The generalized binomial theorem as a consequence of @{thm E_add_mult} *}
+
+lemma gbinomial_theorem:
+ "((a::'a::{field_char_0, division_by_zero})+b) ^ n = (\<Sum>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 = (\<Sum>i\<Colon>nat = 0\<Colon>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
+ apply (rule setsum_cong2)
+ apply simp
+ apply (frule binomial_fact[where ?'a = 'a, symmetric])
+ by (simp add: field_simps of_nat_mult)
+qed
+
+text{* And the nat-form -- also available from Binomial.thy *}
+lemma binomial_theorem: "(a+b) ^ n = (\<Sum>k=0..n. (n choose k) * a^k * b^(n-k))"
+ using gbinomial_theorem[of "of_nat a" "of_nat b" n]
+ unfolding of_nat_add[symmetric] of_nat_power[symmetric] of_nat_mult[symmetric] of_nat_setsum[symmetric]
+ by simp
+
subsubsection{* Logarithmic series *}
lemma Abs_fps_if_0:
@@ -2679,6 +2701,278 @@
unfolding fps_deriv_eq_iff by simp
qed
+subsubsection{* Binomial series *}
+
+definition "fps_binomial a = Abs_fps (\<lambda>n. a gchoose n)"
+
+lemma fps_binomial_nth[simp]: "fps_binomial a $ n = a gchoose n"
+ by (simp add: fps_binomial_def)
+
+lemma fps_binomial_ODE_unique:
+ fixes c :: "'a::field_char_0"
+ shows "fps_deriv a = (fps_const c * a) / (1 + X) \<longleftrightarrow> a = fps_const (a$0) * fps_binomial c"
+ (is "?lhs \<longleftrightarrow> ?rhs")
+proof-
+ let ?da = "fps_deriv a"
+ let ?x1 = "(1 + X):: 'a fps"
+ let ?l = "?x1 * ?da"
+ let ?r = "fps_const c * a"
+ have x10: "?x1 $ 0 \<noteq> 0" by simp
+ have "?l = ?r \<longleftrightarrow> inverse ?x1 * ?l = inverse ?x1 * ?r" by simp
+ also have "\<dots> \<longleftrightarrow> ?da = (fps_const c * a) / ?x1"
+ apply (simp only: fps_divide_def mult_assoc[symmetric] inverse_mult_eq_1[OF x10])
+ by (simp add: ring_simps)
+ finally have eq: "?l = ?r \<longleftrightarrow> ?lhs" by simp
+ moreover
+ {assume h: "?l = ?r"
+ {fix n
+ from h have lrn: "?l $ n = ?r$n" by simp
+
+ from lrn
+ have "a$ Suc n = ((c - of_nat n) / of_nat (Suc n)) * a $n"
+ apply (simp add: ring_simps del: of_nat_Suc)
+ by (cases n, simp_all add: field_simps del: of_nat_Suc)
+ }
+ note th0 = this
+ {fix n have "a$n = (c gchoose n) * a$0"
+ proof(induct n)
+ case 0 thus ?case by simp
+ next
+ case (Suc m)
+ thus ?case unfolding th0
+ apply (simp add: field_simps del: of_nat_Suc)
+ unfolding mult_assoc[symmetric] gbinomial_mult_1
+ by (simp add: ring_simps)
+ qed}
+ note th1 = this
+ have ?rhs
+ apply (simp add: fps_eq_iff)
+ apply (subst th1)
+ by (simp add: ring_simps)}
+ moreover
+ {assume h: ?rhs
+ have th00:"\<And>x y. x * (a$0 * y) = a$0 * (x*y)" by (simp add: mult_commute)
+ have "?l = ?r"
+ apply (subst h)
+ apply (subst (2) h)
+ apply (clarsimp simp add: fps_eq_iff ring_simps)
+ unfolding mult_assoc[symmetric] th00 gbinomial_mult_1
+ by (simp add: ring_simps gbinomial_mult_1)}
+ ultimately show ?thesis by blast
+qed
+
+lemma fps_binomial_deriv: "fps_deriv (fps_binomial c) = fps_const c * fps_binomial c / (1 + X)"
+proof-
+ let ?a = "fps_binomial c"
+ have th0: "?a = fps_const (?a$0) * ?a" by (simp)
+ from iffD2[OF fps_binomial_ODE_unique, OF th0] show ?thesis .
+qed
+
+lemma fps_binomial_add_mult: "fps_binomial (c+d) = fps_binomial c * fps_binomial d" (is "?l = ?r")
+proof-
+ let ?P = "?r - ?l"
+ let ?b = "fps_binomial"
+ let ?db = "\<lambda>x. fps_deriv (?b x)"
+ have "fps_deriv ?P = ?db c * ?b d + ?b c * ?db d - ?db (c + d)" by simp
+ also have "\<dots> = inverse (1 + X) * (fps_const c * ?b c * ?b d + fps_const d * ?b c * ?b d - fps_const (c+d) * ?b (c + d))"
+ unfolding fps_binomial_deriv
+ by (simp add: fps_divide_def ring_simps)
+ also have "\<dots> = (fps_const (c + d)/ (1 + X)) * ?P"
+ by (simp add: ring_simps fps_divide_def fps_const_add[symmetric] del: fps_const_add)
+ finally have th0: "fps_deriv ?P = fps_const (c+d) * ?P / (1 + X)"
+ by (simp add: fps_divide_def)
+ have "?P = fps_const (?P$0) * ?b (c + d)"
+ unfolding fps_binomial_ODE_unique[symmetric]
+ using th0 by simp
+ hence "?P = 0" by (simp add: fps_mult_nth)
+ then show ?thesis by simp
+qed
+
+lemma fps_minomial_minus_one: "fps_binomial (- 1) = inverse (1 + X)"
+ (is "?l = inverse ?r")
+proof-
+ have th: "?r$0 \<noteq> 0" by simp
+ have th': "fps_deriv (inverse ?r) = fps_const (- 1) * inverse ?r / (1 + X)"
+ by (simp add: fps_inverse_deriv[OF th] fps_divide_def power2_eq_square mult_commute fps_const_neg[symmetric] del: fps_const_neg)
+ have eq: "inverse ?r $ 0 = 1"
+ by (simp add: fps_inverse_def)
+ from iffD1[OF fps_binomial_ODE_unique[of "inverse (1 + X)" "- 1"] th'] eq
+ show ?thesis by (simp add: fps_inverse_def)
+qed
+
+text{* Vandermonde's Identity as a consequence *}
+lemma gbinomial_Vandermonde: "setsum (\<lambda>k. (a gchoose k) * (b gchoose (n - k))) {0..n} = (a + b) gchoose n"
+proof-
+ let ?ba = "fps_binomial a"
+ let ?bb = "fps_binomial b"
+ let ?bab = "fps_binomial (a + b)"
+ from fps_binomial_add_mult[of a b] have "?bab $ n = (?ba * ?bb)$n" by simp
+ then show ?thesis by (simp add: fps_mult_nth)
+qed
+
+lemma binomial_Vandermonde: "setsum (\<lambda>k. (a choose k) * (b choose (n - k))) {0..n} = (a + b) choose n"
+ using gbinomial_Vandermonde[of "(of_nat a)" "of_nat b" n]
+
+ apply (simp only: binomial_gbinomial[symmetric] of_nat_mult[symmetric] of_nat_setsum[symmetric] of_nat_add[symmetric])
+ by simp
+
+lemma binomial_Vandermonde_same: "setsum (\<lambda>k. (n choose k)^2) {0..n} = (2*n) choose n"
+ using binomial_Vandermonde[of n n n,symmetric]
+ unfolding nat_mult_2 apply (simp add: power2_eq_square)
+ apply (rule setsum_cong2)
+ by (auto intro: binomial_symmetric)
+
+lemma Vandermonde_pochhammer_lemma:
+ fixes a :: "'a::field_char_0"
+ assumes b: "\<forall> j\<in>{0 ..<n}. b \<noteq> of_nat j"
+ shows "setsum (%k. (pochhammer (- a) k * pochhammer (- (of_nat n)) k) / (of_nat (fact k) * pochhammer (b - of_nat n + 1) k)) {0..n} = pochhammer (- (a+ b)) n / pochhammer (- b) n" (is "?l = ?r")
+proof-
+ let ?m1 = "%m. (- 1 :: 'a) ^ m"
+ let ?f = "%m. of_nat (fact m)"
+ let ?p = "%(x::'a). pochhammer (- x)"
+ from b have bn0: "?p b n \<noteq> 0" unfolding pochhammer_eq_0_iff by simp
+ {fix k assume kn: "k \<in> {0..n}"
+ {assume c:"pochhammer (b - of_nat n + 1) n = 0"
+ then obtain j where j: "j < n" "b - of_nat n + 1 = - of_nat j"
+ unfolding pochhammer_eq_0_iff by blast
+ from j have "b = of_nat n - of_nat j - of_nat 1"
+ by (simp add: algebra_simps)
+ then have "b = of_nat (n - j - 1)"
+ using j kn by (simp add: of_nat_diff)
+ with b have False using j by auto}
+ then have nz: "pochhammer (1 + b - of_nat n) n \<noteq> 0"
+ by (auto simp add: algebra_simps)
+
+ from nz kn have nz': "pochhammer (1 + b - of_nat n) k \<noteq> 0"
+ by (simp add: pochhammer_neq_0_mono)
+ {assume k0: "k = 0 \<or> n =0"
+ then have "b gchoose (n - k) = (?m1 n * ?p b n * ?m1 k * ?p (of_nat n) k) / (?f n * pochhammer (b - of_nat n + 1) k)"
+ using kn
+ by (cases "k=0", simp_all add: gbinomial_pochhammer)}
+ moreover
+ {assume n0: "n \<noteq> 0" and k0: "k \<noteq> 0"
+ then obtain m where m: "n = Suc m" by (cases n, auto)
+ from k0 obtain h where h: "k = Suc h" by (cases k, auto)
+ {assume kn: "k = n"
+ then have "b gchoose (n - k) = (?m1 n * ?p b n * ?m1 k * ?p (of_nat n) k) / (?f n * pochhammer (b - of_nat n + 1) k)"
+ using kn pochhammer_minus'[where k=k and n=n and b=b]
+ apply (simp add: pochhammer_same)
+ using bn0
+ by (simp add: field_simps power_add[symmetric])}
+ moreover
+ {assume nk: "k \<noteq> n"
+ have m1nk: "?m1 n = setprod (%i. - 1) {0..m}"
+ "?m1 k = setprod (%i. - 1) {0..h}"
+ by (simp_all add: setprod_constant m h)
+ from kn nk have kn': "k < n" by simp
+ have bnz0: "pochhammer (b - of_nat n + 1) k \<noteq> 0"
+ using bn0 kn
+ unfolding pochhammer_eq_0_iff
+ apply auto
+ apply (erule_tac x= "n - ka - 1" in allE)
+ by (auto simp add: algebra_simps of_nat_diff)
+ have eq1: "setprod (%k. (1::'a) + of_nat m - of_nat k) {0 .. h} = setprod of_nat {Suc (m - h) .. Suc m}"
+ apply (rule strong_setprod_reindex_cong[where f="%k. Suc m - k "])
+ using kn' h m
+ apply (auto simp add: inj_on_def image_def)
+ apply (rule_tac x="Suc m - x" in bexI)
+ apply (simp_all add: of_nat_diff)
+ done
+
+ have th1: "(?m1 k * ?p (of_nat n) k) / ?f n = 1 / of_nat(fact (n - k))"
+ unfolding m1nk
+
+ unfolding m h pochhammer_Suc_setprod
+ apply (simp add: field_simps del: fact_Suc id_def)
+ unfolding fact_altdef_nat id_def
+ unfolding of_nat_setprod
+ unfolding setprod_timesf[symmetric]
+ apply auto
+ unfolding eq1
+ apply (subst setprod_Un_disjoint[symmetric])
+ apply (auto)
+ apply (rule setprod_cong)
+ apply auto
+ done
+ have th20: "?m1 n * ?p b n = setprod (%i. b - of_nat i) {0..m}"
+ unfolding m1nk
+ unfolding m h pochhammer_Suc_setprod
+ unfolding setprod_timesf[symmetric]
+ apply (rule setprod_cong)
+ apply auto
+ done
+ have th21:"pochhammer (b - of_nat n + 1) k = setprod (%i. b - of_nat i) {n - k .. n - 1}"
+ unfolding h m
+ unfolding pochhammer_Suc_setprod
+ apply (rule strong_setprod_reindex_cong[where f="%k. n - 1 - k"])
+ using kn
+ apply (auto simp add: inj_on_def m h image_def)
+ apply (rule_tac x= "m - x" in bexI)
+ by (auto simp add: of_nat_diff)
+
+ have "?m1 n * ?p b n = pochhammer (b - of_nat n + 1) k * setprod (%i. b - of_nat i) {0.. n - k - 1}"
+ unfolding th20 th21
+ unfolding h m
+ apply (subst setprod_Un_disjoint[symmetric])
+ using kn' h m
+ apply auto
+ apply (rule setprod_cong)
+ apply auto
+ done
+ then have th2: "(?m1 n * ?p b n)/pochhammer (b - of_nat n + 1) k = setprod (%i. b - of_nat i) {0.. n - k - 1}"
+ using nz' by (simp add: field_simps)
+ have "(?m1 n * ?p b n * ?m1 k * ?p (of_nat n) k) / (?f n * pochhammer (b - of_nat n + 1) k) = ((?m1 k * ?p (of_nat n) k) / ?f n) * ((?m1 n * ?p b n)/pochhammer (b - of_nat n + 1) k)"
+ using bnz0
+ by (simp add: field_simps)
+ also have "\<dots> = b gchoose (n - k)"
+ unfolding th1 th2
+ using kn' by (simp add: gbinomial_def)
+ finally have "b gchoose (n - k) = (?m1 n * ?p b n * ?m1 k * ?p (of_nat n) k) / (?f n * pochhammer (b - of_nat n + 1) k)" by simp}
+ ultimately have "b gchoose (n - k) = (?m1 n * ?p b n * ?m1 k * ?p (of_nat n) k) / (?f n * pochhammer (b - of_nat n + 1) k)"
+ by (cases "k =n", auto)}
+ ultimately have "b gchoose (n - k) = (?m1 n * ?p b n * ?m1 k * ?p (of_nat n) k) / (?f n * pochhammer (b - of_nat n + 1) k)" "pochhammer (1 + b - of_nat n) k \<noteq> 0 "
+ using nz'
+ apply (cases "n=0", auto)
+ by (cases "k", auto)}
+ note th00 = this
+ have "?r = ((a + b) gchoose n) * (of_nat (fact n)/ (?m1 n * pochhammer (- b) n))"
+ unfolding gbinomial_pochhammer
+ using bn0 by (auto simp add: field_simps)
+ also have "\<dots> = ?l"
+ unfolding gbinomial_Vandermonde[symmetric]
+ apply (simp add: th00)
+ unfolding gbinomial_pochhammer
+ using bn0 apply (simp add: setsum_left_distrib setsum_right_distrib field_simps)
+ apply (rule setsum_cong2)
+ apply (drule th00(2))
+ by (simp add: field_simps power_add[symmetric])
+ finally show ?thesis by simp
+qed
+
+
+lemma Vandermonde_pochhammer:
+ fixes a :: "'a::field_char_0"
+ assumes c: "ALL i : {0..< n}. c \<noteq> - of_nat i"
+ shows "setsum (%k. (pochhammer a k * pochhammer (- (of_nat n)) k) / (of_nat (fact k) * pochhammer c k)) {0..n} = pochhammer (c - a) n / pochhammer c n"
+proof-
+ let ?a = "- a"
+ let ?b = "c + of_nat n - 1"
+ have h: "\<forall> j \<in>{0..< n}. ?b \<noteq> of_nat j" using c
+ apply (auto simp add: algebra_simps of_nat_diff)
+ apply (erule_tac x= "n - j - 1" in ballE)
+ by (auto simp add: of_nat_diff algebra_simps)
+ have th0: "pochhammer (- (?a + ?b)) n = (- 1)^n * pochhammer (c - a) n"
+ unfolding pochhammer_minus[OF le_refl]
+ by (simp add: algebra_simps)
+ have th1: "pochhammer (- ?b) n = (- 1)^n * pochhammer c n"
+ unfolding pochhammer_minus[OF le_refl]
+ by simp
+ have nz: "pochhammer c n \<noteq> 0" using c
+ by (simp add: pochhammer_eq_0_iff)
+ from Vandermonde_pochhammer_lemma[where a = "?a" and b="?b" and n=n, OF h, unfolded th0 th1]
+ show ?thesis using nz by (simp add: field_simps setsum_right_distrib)
+qed
+
subsubsection{* Formal trigonometric functions *}
definition "fps_sin (c::'a::field_char_0) =
@@ -2866,4 +3160,170 @@
by simp
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 "
+ (is "?l = ?r")
+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)}
+ moreover
+ {assume on: "odd n"
+ from on obtain m where m: "n = 2*m + 1"
+ unfolding odd_nat_equiv_def2 by (auto simp add: nat_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)
+qed
+
+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)"
+ by (simp add: fps_eq_iff fps_const_def)
+
+lemma fps_number_of_fps_const: "number_of i = fps_const (number_of i :: 'a:: {comm_ring_1, number_ring})"
+ apply (subst (2) number_of_eq)
+apply(rule int_induct[of _ 0])
+apply (simp_all add: number_of_fps_def)
+by (simp_all add: fps_const_add[symmetric] fps_const_minus[symmetric])
+
+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: fps_eq_iff fps_number_of_fps_const complex_number_of_def[symmetric])
+ show ?thesis
+ unfolding Eii_sin_cos minus_mult_commute
+ by (simp add: fps_sin_even fps_cos_odd fps_number_of_fps_const
+ fps_divide_def fps_const_inverse th complex_number_of_def[symmetric])
+qed
+
+lemma fps_sin_Eii:
+ "fps_sin c = (E (ii * c) - E (- ii * c)) / fps_const (2*ii)"
+proof-
+ have th: "fps_const \<i> * fps_sin c + fps_const \<i> * fps_sin c = fps_sin c * fps_const (2 * ii)"
+ by (simp add: fps_eq_iff fps_number_of_fps_const complex_number_of_def[symmetric])
+ 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)
+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
+
+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, division_by_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:
+ "foldl (%r x. r * f x) (v::'a::comm_ring_1) as * x = foldl (%r x. r * f x) (v * x) as "
+ by (induct as arbitrary: x v, auto simp add: algebra_simps)
+
+lemma foldr_mult_foldl: "foldr (%x r. r * f x) as v = foldl (%r x. r * f x) (v :: 'a::comm_ring_1) as"
+ by (induct as arbitrary: v, auto simp add: foldl_mult_start)
+
+lemma F_nth_alt: "F as bs c $ n = foldr (\<lambda>a r. r * pochhammer a n) as (c ^ n) /
+ foldr (\<lambda>b r. r * pochhammer b n) bs (of_nat (fact n))"
+ by (simp add: foldl_mult_start foldr_mult_foldl)
+
+lemma F_E[simp]: "F [] [] c = E c"
+ by (simp add: fps_eq_iff)
+
+lemma F_1_0[simp]: "F [1] [] c = 1/(1 - fps_const c * X)"
+proof-
+ let ?a = "(Abs_fps (\<lambda>n. 1)) oo (fps_const c * X)"
+ have th0: "(fps_const c * X) $ 0 = 0" by simp
+ show ?thesis unfolding gp[OF th0, symmetric]
+ by (auto simp add: fps_eq_iff pochhammer_fact[symmetric] fps_compose_nth power_mult_distrib cond_value_iff setsum_delta' cong del: if_weak_cong)
+qed
+
+lemma F_B[simp]: "F [-a] [] (- 1) = fps_binomial a"
+ by (simp add: fps_eq_iff gbinomial_pochhammer algebra_simps)
+
+lemma F_0[simp]: "F as bs c $0 = 1"
+ apply simp
+ apply (subgoal_tac "ALL as. foldl (%(r::'a) (a::'a). r) 1 as = 1")
+ apply auto
+ apply (induct_tac as, 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"
+ by (induct as arbitrary: v w, auto simp add: algebra_simps)
+
+
+lemma F_rec: "F as bs c $ Suc n = ((foldl (%r a. r* (a + of_nat n)) c as)/ (foldl (%r b. r * (b + of_nat n)) (of_nat (Suc n)) bs )) * F as bs c $ n"
+ 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)
+
+lemma XD_nth[simp]: "XD a $ n = (if n=0 then 0 else of_nat n * a$n)"
+ by (simp add: XD_def)
+
+lemma XD_0th[simp]: "XD a $ 0 = 0" by simp
+lemma XD_Suc[simp]:" XD a $ Suc n = of_nat (Suc n) * a $ Suc n" by simp
+
+definition "XDp c a = XD a + fps_const c * a"
+
+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"
+ by (auto simp add: XDp_def expand_fun_eq fps_eq_iff algebra_simps)
+
+lemma XDp0[simp]: "XDp 0 = XD"
+ by (simp add: expand_fun_eq fps_eq_iff)
+
+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, division_by_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, division_by_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 =
+ 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"
+
+ 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)"
+ by (induct cs arbitrary: c0, auto simp add: algebra_simps f )
+
end
--- a/src/HOL/ex/Formal_Power_Series_Examples.thy Thu Jul 23 22:20:37 2009 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,303 +0,0 @@
-(* Title: Formal_Power_Series_Examples.thy
- ID:
- Author: Amine Chaieb, University of Cambridge
-*)
-
-header{* Some applications of formal power series and some properties over complex numbers*}
-
-theory Formal_Power_Series_Examples
- imports Formal_Power_Series Binomial
-begin
-
-section{* The generalized binomial theorem *}
-lemma gbinomial_theorem:
- "((a::'a::{field_char_0, division_by_zero})+b) ^ n = (\<Sum>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 = (\<Sum>i\<Colon>nat = 0\<Colon>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
- apply (rule setsum_cong2)
- apply simp
- apply (frule binomial_fact[where ?'a = 'a, symmetric])
- by (simp add: field_simps of_nat_mult)
-qed
-
-text{* And the nat-form -- also available from Binomial.thy *}
-lemma binomial_theorem: "(a+b) ^ n = (\<Sum>k=0..n. (n choose k) * a^k * b^(n-k))"
- using gbinomial_theorem[of "of_nat a" "of_nat b" n]
- unfolding of_nat_add[symmetric] of_nat_power[symmetric] of_nat_mult[symmetric] of_nat_setsum[symmetric]
- by simp
-
-section {* The binomial series and Vandermonde's identity *}
-definition "fps_binomial a = Abs_fps (\<lambda>n. a gchoose n)"
-
-lemma fps_binomial_nth[simp]: "fps_binomial a $ n = a gchoose n"
- by (simp add: fps_binomial_def)
-
-lemma fps_binomial_ODE_unique:
- fixes c :: "'a::field_char_0"
- shows "fps_deriv a = (fps_const c * a) / (1 + X) \<longleftrightarrow> a = fps_const (a$0) * fps_binomial c"
- (is "?lhs \<longleftrightarrow> ?rhs")
-proof-
- let ?da = "fps_deriv a"
- let ?x1 = "(1 + X):: 'a fps"
- let ?l = "?x1 * ?da"
- let ?r = "fps_const c * a"
- have x10: "?x1 $ 0 \<noteq> 0" by simp
- have "?l = ?r \<longleftrightarrow> inverse ?x1 * ?l = inverse ?x1 * ?r" by simp
- also have "\<dots> \<longleftrightarrow> ?da = (fps_const c * a) / ?x1"
- apply (simp only: fps_divide_def mult_assoc[symmetric] inverse_mult_eq_1[OF x10])
- by (simp add: ring_simps)
- finally have eq: "?l = ?r \<longleftrightarrow> ?lhs" by simp
- moreover
- {assume h: "?l = ?r"
- {fix n
- from h have lrn: "?l $ n = ?r$n" by simp
-
- from lrn
- have "a$ Suc n = ((c - of_nat n) / of_nat (Suc n)) * a $n"
- apply (simp add: ring_simps del: of_nat_Suc)
- by (cases n, simp_all add: field_simps del: of_nat_Suc)
- }
- note th0 = this
- {fix n have "a$n = (c gchoose n) * a$0"
- proof(induct n)
- case 0 thus ?case by simp
- next
- case (Suc m)
- thus ?case unfolding th0
- apply (simp add: field_simps del: of_nat_Suc)
- unfolding mult_assoc[symmetric] gbinomial_mult_1
- by (simp add: ring_simps)
- qed}
- note th1 = this
- have ?rhs
- apply (simp add: fps_eq_iff)
- apply (subst th1)
- by (simp add: ring_simps)}
- moreover
- {assume h: ?rhs
- have th00:"\<And>x y. x * (a$0 * y) = a$0 * (x*y)" by (simp add: mult_commute)
- have "?l = ?r"
- apply (subst h)
- apply (subst (2) h)
- apply (clarsimp simp add: fps_eq_iff ring_simps)
- unfolding mult_assoc[symmetric] th00 gbinomial_mult_1
- by (simp add: ring_simps gbinomial_mult_1)}
- ultimately show ?thesis by blast
-qed
-
-lemma fps_binomial_deriv: "fps_deriv (fps_binomial c) = fps_const c * fps_binomial c / (1 + X)"
-proof-
- let ?a = "fps_binomial c"
- have th0: "?a = fps_const (?a$0) * ?a" by (simp)
- from iffD2[OF fps_binomial_ODE_unique, OF th0] show ?thesis .
-qed
-
-lemma fps_binomial_add_mult: "fps_binomial (c+d) = fps_binomial c * fps_binomial d" (is "?l = ?r")
-proof-
- let ?P = "?r - ?l"
- let ?b = "fps_binomial"
- let ?db = "\<lambda>x. fps_deriv (?b x)"
- have "fps_deriv ?P = ?db c * ?b d + ?b c * ?db d - ?db (c + d)" by simp
- also have "\<dots> = inverse (1 + X) * (fps_const c * ?b c * ?b d + fps_const d * ?b c * ?b d - fps_const (c+d) * ?b (c + d))"
- unfolding fps_binomial_deriv
- by (simp add: fps_divide_def ring_simps)
- also have "\<dots> = (fps_const (c + d)/ (1 + X)) * ?P"
- by (simp add: ring_simps fps_divide_def fps_const_add[symmetric] del: fps_const_add)
- finally have th0: "fps_deriv ?P = fps_const (c+d) * ?P / (1 + X)"
- by (simp add: fps_divide_def)
- have "?P = fps_const (?P$0) * ?b (c + d)"
- unfolding fps_binomial_ODE_unique[symmetric]
- using th0 by simp
- hence "?P = 0" by (simp add: fps_mult_nth)
- then show ?thesis by simp
-qed
-
-lemma fps_minomial_minus_one: "fps_binomial (- 1) = inverse (1 + X)"
- (is "?l = inverse ?r")
-proof-
- have th: "?r$0 \<noteq> 0" by simp
- have th': "fps_deriv (inverse ?r) = fps_const (- 1) * inverse ?r / (1 + X)"
- by (simp add: fps_inverse_deriv[OF th] fps_divide_def power2_eq_square mult_commute fps_const_neg[symmetric] del: fps_const_neg)
- have eq: "inverse ?r $ 0 = 1"
- by (simp add: fps_inverse_def)
- from iffD1[OF fps_binomial_ODE_unique[of "inverse (1 + X)" "- 1"] th'] eq
- show ?thesis by (simp add: fps_inverse_def)
-qed
-
-lemma gbinomial_Vandermond: "setsum (\<lambda>k. (a gchoose k) * (b gchoose (n - k))) {0..n} = (a + b) gchoose n"
-proof-
- let ?ba = "fps_binomial a"
- let ?bb = "fps_binomial b"
- let ?bab = "fps_binomial (a + b)"
- from fps_binomial_add_mult[of a b] have "?bab $ n = (?ba * ?bb)$n" by simp
- then show ?thesis by (simp add: fps_mult_nth)
-qed
-
-lemma binomial_Vandermond: "setsum (\<lambda>k. (a choose k) * (b choose (n - k))) {0..n} = (a + b) choose n"
- using gbinomial_Vandermond[of "(of_nat a)" "of_nat b" n]
-
- apply (simp only: binomial_gbinomial[symmetric] of_nat_mult[symmetric] of_nat_setsum[symmetric] of_nat_add[symmetric])
- by simp
-
-lemma binomial_symmetric: assumes kn: "k \<le> n"
- shows "n choose k = n choose (n - k)"
-proof-
- from kn have kn': "n - k \<le> n" by arith
- from binomial_fact_lemma[OF kn] binomial_fact_lemma[OF kn']
- have "fact k * fact (n - k) * (n choose k) = fact (n - k) * fact (n - (n - k)) * (n choose (n - k))" by simp
- then show ?thesis using kn by simp
-qed
-
-lemma binomial_Vandermond_same: "setsum (\<lambda>k. (n choose k)^2) {0..n} = (2*n) choose n"
- using binomial_Vandermond[of n n n,symmetric]
- unfolding nat_mult_2 apply (simp add: power2_eq_square)
- apply (rule setsum_cong2)
- by (auto intro: binomial_symmetric)
-
-section {* Relation between formal sine/cosine and the exponential FPS*}
-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"
- 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)}
- moreover
- {assume on: "odd n"
- from on obtain m where m: "n = 2*m + 1"
- unfolding odd_nat_equiv_def2 by (auto simp add: nat_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)
-qed
-
-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)"
- by (simp add: fps_eq_iff fps_const_def)
-
-lemma fps_number_of_fps_const: "number_of i = fps_const (number_of i :: 'a:: {comm_ring_1, number_ring})"
- apply (subst (2) number_of_eq)
-apply(rule int_induct[of _ 0])
-apply (simp_all add: number_of_fps_def)
-by (simp_all add: fps_const_add[symmetric] fps_const_minus[symmetric])
-
-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: fps_eq_iff fps_number_of_fps_const complex_number_of_def[symmetric])
- show ?thesis
- unfolding Eii_sin_cos minus_mult_commute
- by (simp add: fps_sin_even fps_cos_odd fps_number_of_fps_const
- fps_divide_def fps_const_inverse th complex_number_of_def[symmetric])
-qed
-
-lemma fps_sin_Eii:
- "fps_sin c = (E (ii * c) - E (- ii * c)) / fps_const (2*ii)"
-proof-
- have th: "fps_const \<i> * fps_sin c + fps_const \<i> * fps_sin c = fps_sin c * fps_const (2 * ii)"
- by (simp add: fps_eq_iff fps_number_of_fps_const complex_number_of_def[symmetric])
- 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)
-qed
-
-lemma fps_const_mult_2: "fps_const (2::'a::number_ring) * a = a +a"
- by (simp add: fps_eq_iff fps_number_of_fps_const)
-
-lemma fps_const_mult_2_right: "a * fps_const (2::'a::number_ring) = a +a"
- by (simp add: fps_eq_iff fps_number_of_fps_const)
-
-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
-
-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)
-
-text{* Now some trigonometric identities *}
-
-lemma fps_sin_add:
- "fps_sin (a+b) = fps_sin (a::complex) * fps_cos b + fps_cos a * fps_sin b"
-proof-
- let ?ca = "fps_cos a"
- let ?cb = "fps_cos b"
- let ?sa = "fps_sin a"
- let ?sb = "fps_sin b"
- let ?i = "fps_const ii"
- have i: "?i*?i = fps_const -1" by simp
- have "fps_sin (a + b) =
- ((?ca + ?i * ?sa) * (?cb + ?i*?sb) - (?ca - ?i*?sa) * (?cb - ?i*?sb)) *
- fps_const (- (\<i> / 2))"
- apply(simp add: fps_sin_Eii[of "a+b"] fps_divide_def minus_mult_commute)
- unfolding right_distrib
- apply (simp add: Eii_sin_cos E_minus_ii_sin_cos fps_const_inverse E_add_mult)
- by (simp add: ring_simps)
- also have "\<dots> = (?ca * ?cb + ?i*?ca * ?sb + ?i * ?sa * ?cb + (?i*?i)*?sa*?sb - ?ca*?cb + ?i*?ca * ?sb + ?i*?sa*?cb - (?i*?i)*?sa * ?sb) * fps_const (- ii/2)"
- by (simp add: ring_simps)
- also have "\<dots> = (fps_const 2 * ?i * (?ca * ?sb + ?sa * ?cb)) * fps_const (- ii/2)"
- apply simp
- apply (simp add: ring_simps)
- apply (simp add: ring_simps add: fps_const_mult[symmetric] del:fps_const_mult)
- unfolding fps_const_mult_2_right
- by (simp add: ring_simps)
- also have "\<dots> = (fps_const 2 * ?i * fps_const (- ii/2)) * (?ca * ?sb + ?sa * ?cb)"
- by (simp only: mult_ac)
- also have "\<dots> = ?sa * ?cb + ?ca*?sb"
- by simp
- finally show ?thesis .
-qed
-
-lemma fps_cos_add:
- "fps_cos (a+b) = fps_cos (a::complex) * fps_cos b - fps_sin a * fps_sin b"
-proof-
- let ?ca = "fps_cos a"
- let ?cb = "fps_cos b"
- let ?sa = "fps_sin a"
- let ?sb = "fps_sin b"
- let ?i = "fps_const ii"
- have i: "?i*?i = fps_const -1" by simp
- have i': "\<And>x. ?i * (?i * x) = - x"
- apply (simp add: mult_assoc[symmetric] i)
- by (simp add: fps_eq_iff)
- have m1: "\<And>x. x * fps_const (-1 ::complex) = - x" "\<And>x. fps_const (-1 :: complex) * x = - x"
- by (auto simp add: fps_eq_iff)
-
- have "fps_cos (a + b) =
- ((?ca + ?i * ?sa) * (?cb + ?i*?sb) + (?ca - ?i*?sa) * (?cb - ?i*?sb)) *
- fps_const (1/ 2)"
- apply(simp add: fps_cos_Eii[of "a+b"] fps_divide_def minus_mult_commute)
- unfolding right_distrib minus_add_distrib
- apply (simp add: Eii_sin_cos E_minus_ii_sin_cos fps_const_inverse E_add_mult)
- by (simp add: ring_simps)
- also have "\<dots> = (?ca * ?cb + ?i*?ca * ?sb + ?i * ?sa * ?cb + (?i*?i)*?sa*?sb + ?ca*?cb - ?i*?ca * ?sb - ?i*?sa*?cb + (?i*?i)*?sa * ?sb) * fps_const (1/2)"
- apply simp
- by (simp add: ring_simps i' m1)
- also have "\<dots> = (fps_const 2 * (?ca * ?cb - ?sa * ?sb)) * fps_const (1/2)"
- apply simp
- by (simp add: ring_simps m1 fps_const_mult_2_right)
- also have "\<dots> = (fps_const 2 * fps_const (1/2)) * (?ca * ?cb - ?sa * ?sb)"
- by (simp only: mult_ac)
- also have "\<dots> = ?ca * ?cb - ?sa*?sb"
- by simp
- finally show ?thesis .
-qed
-
-end