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isa-afp
afp-devel
Commits
1edcb594d89c
Commit
2dc75c2d
authored
Apr 30, 2021
by
Rene Thiemann
Browse files
cleaning proofs, use more real_asymp
parent
72edb20655d6
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-111
thys/Perron_Frobenius/Spectral_Radius_Largest_Jordan_Block.thy
...Perron_Frobenius/Spectral_Radius_Largest_Jordan_Block.thy
+122
-111
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thys/Perron_Frobenius/Spectral_Radius_Largest_Jordan_Block.thy
View file @
1edcb594
...
...
@@ -221,13 +221,36 @@ proof -
finally show ?thesis using A by auto
qed
definition "c = (\<Prod>ia = 0..<m-1. (of_nat m :: real) - 1 - of_nat ia)"
lemma c_gt_0: "c > 0" unfolding c_def by (rule prod_pos, auto)
definition p :: "nat \<Rightarrow> real poly" where
"p s = (\<Prod>i = 0..<s. [: - of_nat i / of_nat (s - i), 1 / of_nat (s - i) :])"
lemma p_binom: assumes sk: "s \<le> k"
shows "of_nat (k choose s) = poly (p s) (of_nat k)"
unfolding binomial_altdef_of_nat[OF assms] p_def poly_prod
proof (rule prod.cong[OF refl], clarsimp, goal_cases)
case (1 i)
with sk have "of_nat (k - i) = (of_nat k - of_nat i :: real)" by auto
thus ?case using 1 by (auto simp: field_simps)
qed
lemma p_binom_complex: assumes sk: "s \<le> k"
shows "of_nat (k choose s) = complex_of_real (poly (p s) (of_nat k))"
unfolding p_binom[OF sk, symmetric] by simp
lemma deg_p: "degree (p s) = s" unfolding p_def
by (subst degree_prod_eq_sum_degree, auto)
lemma lead_coeff_p: "lead_coeff (p s) = (\<Prod>i = 0..<s. 1 / (of_nat s - of_nat i))"
unfolding p_def lead_coeff_prod
by (rule prod.cong[OF refl], auto)
lemma lead_coeff_p_gt_0: "lead_coeff (p s) > 0" unfolding lead_coeff_p
by (rule prod_pos, auto)
definition "c = lead_coeff (p (m - 1))"
lemma c_gt_0: "c > 0" unfolding c_def by (rule lead_coeff_p_gt_0)
lemma c0: "c \<noteq> 0" using c_gt_0 by auto
lemma c_int_def: "c = (\<Prod>ia = 0..<m-1. (of_nat m :: int) - 1 - of_nat ia)"
using c_def by auto
lemma c_int: "c \<in> \<int>" using c_int_def Ints_of_int by metis
lemma c_ge_1: "c \<ge> 1" using c_gt_0 unfolding c_int_def by presburger
definition PP where "PP = (SOME PP. similar_mat_wit cA J (fst PP) (snd PP))"
definition P where "P = fst PP"
...
...
@@ -302,7 +325,7 @@ definition f where "f off k = D * k + (m-1) + off"
lemma mono_f: "strict_mono (f off)" unfolding strict_mono_def f_def
using D0 by auto
definition C where "C off k = (c
/
real (f off k) ^ (m - 1))"
definition C where "C off k =
inverse
(c
*
real (f off k) ^ (m - 1))"
lemma limit_jordan_block: assumes kla: "(k, la) \<in> set n_as"
and ij: "i < k" "j < k"
...
...
@@ -326,14 +349,16 @@ proof -
obtain ks small where decomp: "decompose_prod_root_unity (char_poly A) = (ks, small)" by force
note pf = perron_frobenius_for_complexity_jnf[OF A n0 nonneg sr1 decomp]
define ji where "ji = j - i"
let ?f = "\<lambda> N. (c / (?r N)^(m-1))"
have ji: "j - i = ji" unfolding ji_def by auto
let ?f = "\<lambda> N. c * (?r N)^(m-1)"
let ?jb = "\<lambda> N. (jordan_block k la ^\<^sub>m N) $$ (i,j)"
let ?jbc = "\<lambda> N. (jordan_block k la ^\<^sub>m N) $$ (i,j)
*
?f N"
let ?jbc = "\<lambda> N. (jordan_block k la ^\<^sub>m N) $$ (i,j)
/
?f N"
define e where "e = (if i = 0 \<and> j = k - 1 \<and> cmod la = 1 \<and> k = m then la^off else 0)"
let ?e1 = "\<lambda> N :: nat.
(\<Prod>ia = 0..<ji. (?c N - ?c ia) / ?c (ji - ia
)) * la ^ (N - j
i
)"
let ?e2 = "\<lambda> N.
(\<Prod>ia = 0..<
ji
.
(?
c
N
- ?c ia) / ?c (ji - ia)) * la ^ (N - ji) * (c / ((?c N^(m-1)))
)"
let ?e1 = "\<lambda> N :: nat.
?cr (poly (p (j - i)) (?r N
)) * la ^ (N
+ i
- j)"
let ?e2 = "\<lambda> N.
?cr (poly (p
ji
)
(?
r
N
) / ?f N) * la ^ (N + i - j
)"
define e2 where "e2 = ?e2"
let ?e3 = "\<lambda> N. (((\<Prod>ia = 0..<ji. (?c N - ?c ia) / ?c (ji - ia))) * la ^ (N - ji)) * ?f N"
let ?e3 = "\<lambda> N. poly (p ji) (?r N) / (c * ?r N ^ (m - 1)) * cmod la ^ (N + i - j)"
define e3 where "e3 = ?e3"
{
assume ij': "i \<le> j" and la0: "la \<noteq> 0"
{
...
...
@@ -342,18 +367,28 @@ proof -
with ij ij' have ji: "j - i \<le> N" and id: "N + i - j = N - ji" unfolding ji_def by auto
have "?jb N = (?c (N choose (j - i)) * la ^ (N + i - j))"
unfolding jordan_block_pow using ij ij' by auto
also have "\<dots> = ?e1 N" unfolding ji_def
unfolding binomial_altdef_of_nat[OF ji] id ji_def
proof (rule arg_cong[of _ _ "\<lambda> x. x * _"], rule prod.cong[OF refl], goal_cases)
case (1 x)
hence "x \<le> N" using \<open>N \<ge> k\<close> ij by auto
thus ?case by (simp add: of_nat_diff)
qed
also have "\<dots> = ?e1 N" by (subst p_binom_complex[OF ji], auto)
finally have id: "?jb N = ?e1 N" .
have "?jbc N = e2 N"
unfolding id e2_def using c_gt_0 by (simp add: norm_mult norm_divide norm_power)
unfolding id e2_def
ji_def
using c_gt_0 by (simp add: norm_mult norm_divide norm_power)
} note jbc = this
have e23: "?e2 N = ?e3 N" for N using c_gt_0 by auto
{
fix n
assume n: "n \<ge> ji"
have "cmod (e2 n) = \<bar>poly (p ji) (?r n) / (c * ?r n ^ (m - 1))\<bar> * cmod la ^ (n + i - j)"
unfolding e2_def norm_mult norm_power norm_of_real by simp
also have "\<bar>poly (p ji) (?r n) / (c * ?r n ^ (m - 1))\<bar> = poly (p ji) (?r n) / (c * real n ^ (m - 1))"
by (intro abs_of_nonneg divide_nonneg_nonneg mult_nonneg_nonneg, insert c_gt_0, auto simp: p_binom[OF n, symmetric])
finally have "cmod (e2 n) = e3 n" unfolding e3_def by auto
} note cmod_e2 = this
{
assume e3: "e3 \<longlonglongrightarrow> 0"
have e2_e3: "\<forall>\<^sub>F x in sequentially. cmod (e2 x) = e3 x"
by (rule eventually_sequentiallyI[of "Suc ji"], insert cmod_e2, auto)
have "e2 \<longlonglongrightarrow> 0"
by (subst tendsto_norm_zero_iff[symmetric], subst tendsto_cong[OF e2_e3], rule e3)
} note e2_via_e3 = this
have "(e2 o f off) \<longlonglongrightarrow> e"
proof (cases "cmod la = 1 \<and> k = m \<and> i = 0 \<and> j = k - 1")
case False
...
...
@@ -364,68 +399,36 @@ proof -
proof cases
case 0
hence e0: "e = 0" unfolding e_def by auto
show ?thesis unfolding e0 0 LIMSEQ_iff e2_def
proof (intro exI[of _ "Suc j
i
"] impI allI, goal_cases)
case (1 r n) thus ?case by (cases "n - j
i
", auto)
show ?thesis unfolding e0 0 LIMSEQ_iff e2_def
ji
proof (intro exI[of _ "Suc j"] impI allI, goal_cases)
case (1 r n) thus ?case by (cases "n
+ i
- j", auto)
qed
next
case small
have e0: "e = 0 * (of_real (if m - 1 = 0 then c else 0))" using small unfolding e_def by auto
show ?thesis unfolding e0 unfolding e23 e2_def
proof (rule tendsto_mult[OF _ tendsto_of_real])
show "(\<lambda>x. c / real x ^ (m - 1)) \<longlonglongrightarrow> (if m - 1 = 0 then c else 0)"
by (cases "m - 1"; real_asymp)
let ?laji = "inverse (la^ji)"
let ?f = "(\<lambda>x. (\<Prod>ia = 0..<ji. (?c x - ?c ia) / ?c (ji - ia)) * la ^ (x - ji))"
let ?g = "\<lambda>x. (\<Prod>ia = 0..<ji. (1 - ?c ia * inverse (?c x)) / ?c (ji - ia)) * (((?c x)^ji * la ^ x) * ?laji)"
have fg: "\<forall>\<^sub>F x in sequentially. ?f x = ?g x"
apply (rule eventually_sequentiallyI[of "Suc ji"])
unfolding prod_pow[symmetric] prod.distrib[symmetric] mult.assoc[symmetric]
unfolding prod_pow mult.assoc
by (rule arg_cong2[of _ _ _ _ "(*)"], rule prod.cong, auto simp: ring_distribs,
insert small, subst power_diff, auto simp: divide_inverse)
have 0: "0 = (\<Prod>ia = 0..<ji. (1 - of_nat ia * 0) / of_nat (ji - ia)) * (0 * ?laji)" by simp
show "?f \<longlonglongrightarrow> 0" unfolding tendsto_cong[OF fg]
proof (subst 0, rule tendsto_mult[OF tendsto_prod tendsto_mult[OF _ tendsto_const]],
intro tendsto_intros inverse_of_nat_tendsto_zero)
show "(\<lambda>x. of_nat x ^ ji * la ^ x) \<longlonglongrightarrow> 0"
by (rule poly_times_exp_tendsto_zero, insert small, auto)
qed auto
define d where "d = cmod la"
from small have d: "0 < d" "d < 1" unfolding d_def by auto
have e0: "e = 0" using small unfolding e_def by auto
show ?thesis unfolding e0
proof (intro e2_via_e3, unfold e3_def d_def[symmetric])
show "(\<lambda>N. poly (p ji) (?r N) / (c * ?r N ^ (m - 1)) * d ^ (N + i - j)) \<longlonglongrightarrow> 0"
unfolding poly_altdef sum_divide_distrib sum_distrib_right
by (intro tendsto_null_sum, insert d c0, real_asymp)
qed
next
case medium
with max_block[OF kla] have "k \<le> m" and 1: "\<And> x. cmod la ^ x = 1" by auto
with ij medium have "ji < m - 1" unfolding ji_def by linarith
then obtain d where m1: "m - 1 = Suc d + ji" using less_iff_Suc_add by auto
with max_block[OF kla] have "k \<le> m" by auto
with ij medium have ji: "ji < m - 1" unfolding ji_def by linarith
have e0: "e = 0" using medium unfolding e_def by auto
have 0: "0 = (\<Prod>ia = 0..<ji. (1 - ?c ia * 0) / ?c (ji - ia)) * (of_real c) * 0" by simp
let ?e = "\<lambda> ia N. if N = 0 then 0 else (1 - ?c ia / ?c N) / ?c (ji - ia)"
let ?f = "\<lambda> ia N. (1 - ?c ia * (1 / ?c N)) / ?c (ji - ia)"
{
fix N
have "e2 N = ((\<Prod>ia = 0..<ji. (?c N - ?c ia) / ?c (ji - ia)) / ?c N ^ ji) * la ^ (N - ji) * (of_real c / ?c N ^ Suc d)"
unfolding medium m1 power_add e2_def by simp
also have "(\<Prod>ia = 0..<ji. (?c N - ?c ia) / ?c (ji - ia)) / ?c N ^ ji
= (\<Prod>ia = 0..<ji. ?e ia N)" unfolding prod_pow[symmetric] prod_dividef[symmetric]
by (cases "?c N = 0", auto simp add: field_simps)
finally have "e2 N = (\<Prod>ia = 0..<ji. ?e ia N) * of_real c * inverse (?c N ^ Suc d) * la ^ (N - ji)"
by (simp add: divide_inverse)
also have "cmod \<dots> = cmod ((\<Prod>ia = 0..<ji. ?e ia N) * of_real c * (inverse (?c N ^ Suc d)))"
unfolding norm_mult norm_power 1 by simp
finally have "cmod (e2 N) = cmod ((\<Prod>ia = 0..<ji. ?e ia N) * of_real c * (inverse (?c N ^ Suc d)))" by simp
} note e2 = this
show ?thesis unfolding e0
apply (rule tendsto_norm_zero_cancel, unfold e2, rule tendsto_norm_zero)
apply (subst (2) 0)
apply (rule tendsto_mult[OF tendsto_mult[OF tendsto_prod tendsto_const] inverse_power_tendsto_zero], goal_cases)
proof -
case (1 i)
let ?g = "\<lambda> x. (1 - ?c i * (1 / of_nat x)) / of_nat (ji - i)"
have eq: "\<forall>\<^sub>F x in sequentially. ?e i x = ?g x"
by (rule eventually_sequentiallyI[of 1], auto)
show "?e i \<longlonglongrightarrow> (1 - ?c i * 0) / ?c (ji - i)"
unfolding tendsto_cong[OF eq] using 1
by (intro tendsto_intros lim_1_over_n, auto)
proof (intro e2_via_e3, unfold e3_def medium power_one mult_1_right)
show "(\<lambda>N. poly (p ji) (?r N) / (c * ?r N ^ (m - 1))) \<longlonglongrightarrow> 0"
unfolding poly_altdef sum_divide_distrib
proof (intro tendsto_null_sum, goal_cases)
case (1 deg)
from deg_p ji have "degree (p ji) < m - 1" by auto
with 1 have "deg < m - 1" by auto
thus ?case using c0 by real_asymp
qed
qed
qed
show "(e2 o f off) \<longlonglongrightarrow> e"
...
...
@@ -433,47 +436,55 @@ proof -
next
case True
hence large: "cmod la = 1" "k = m" "i = 0" "j = k - 1" by auto
hence e: "e = la^off" unfolding e_def by auto
hence e: "e = la^off"
and ji: "ji = m - 1"
unfolding e_def
ji_def
by auto
from large k0 have m0: "m \<ge> 1" by auto
define m1 where "m1 = m - 1"
have id: "(real (m - 1) - real ia) = ?r m - 1 - ?r ia" for ia using m0 unfolding m1_def by auto
let ?e4 = "\<lambda> x. (\<Prod>ia = 0..<m1. 1 - ?cr (?r ia / x))"
define q where "q = p m1 - monom c m1"
hence pji: "p ji = q + monom c m1" unfolding q_def ji m1_def by simp
let ?e4a = "\<lambda> x. (complex_of_real (poly q (real x) / (c * real x ^ m1))) * la ^ (x + i - j)"
let ?e4b = "\<lambda> x. la ^ (x + i - j)"
{
fix x :: nat
assume x: "x \<noteq> 0"
have "?e2 x = ((\<Prod>ia = 0..<m1. (?c x - ?c ia) / ?c (m1 - ia)) *
(\<Prod>ia = 0..<m1. ?cr (real m1 - real ia))) /
(\<Prod>i = 0..<m1. ?c x) * la ^ (x - (m-1))" (is "_ = ?A / ?B * ?C")
unfolding m1_def ji_def large c_def prod_pow[symmetric] id by simp
also have "?A = (\<Prod>ia = 0..<m1. (?cr x - ?c ia))" (is "_ = ?A")
unfolding prod.distrib[symmetric] by (rule prod.cong[OF refl], subst of_nat_diff, auto)
also have "?A / ?B = (\<Prod>ia = 0..<m1. 1 - ?cr (?r ia / x))"
unfolding prod_dividef[symmetric] by (rule prod.cong[OF refl], insert x, auto simp: field_simps)
finally have "?e2 x = ?e4 x * ?C" .
} note main = this
from d[OF kla large(1)] have 1: "la ^ d la = 1" by auto
from split_list[OF kla] obtain as bs where n_as: "n_as = as @ (k,la) # bs" by auto
obtain C where D: "D = d la * C" unfolding D_def unfolding n_as using large by auto
have "(\<lambda> x. ?e4 x * e) \<longlonglongrightarrow> (\<Prod>ia = 0..<m1. 1 - ?cr 0) * e"
by (intro tendsto_intros real_tendsto_divide_at_top, auto simp: filterlim_real_sequentially)
also have "(\<Prod>ia = 0..<m1. 1 - ?cr 0) = 1" unfolding e by simp
finally have "(\<lambda> x. ?e4 x * e) \<longlonglongrightarrow> e" by auto
from LIMSEQ_subseq_LIMSEQ[OF this mono_f]
have e4: "(\<lambda> k. (?e4 o f off) k * e) \<longlonglongrightarrow> e" (is "?A \<longlonglongrightarrow> e")
by (auto simp: o_def)
{
fix k :: nat
assume k: "k \<noteq> 0"
hence 0: "f off k \<noteq> 0" unfolding f_def using D0 by auto
have "?e2 (f off k) = ?e4 (f off k) * la^(f off k - (m-1))" unfolding main[OF 0] ..
also have "f off k - (m-1) = D * k + off" unfolding f_def by simp
also have "la ^ \<dots> = e" unfolding e power_add D power_mult 1 by auto
finally have "e2 (f off k) = (?e4 o f off) k * e" unfolding o_def e2_def .
} note main = this
have id: "(?A \<longlonglongrightarrow> e) = ((e2 o f off) \<longlonglongrightarrow> e)"
by (rule tendsto_cong, unfold eventually_at_top_linorder,
rule exI[of _ 1], insert main, auto)
from e4[unfolded id] show ?thesis .
have "e2 x = ?e4a x + ?e4b x"
unfolding e2_def pji poly_add poly_monom m1_def[symmetric] using c0 x by (simp add: field_simps)
} note e2_e4 = this
have e2_e4: "\<forall>\<^sub>F x in sequentially. (e2 o f off) x = (?e4a o f off) x + (?e4b o f off) x" unfolding o_def
by (intro eventually_sequentiallyI[of "Suc 0"], rule e2_e4, insert D0, auto simp: f_def)
have "(e2 o f off) \<longlonglongrightarrow> 0 + e"
unfolding tendsto_cong[OF e2_e4]
proof (rule tendsto_add, rule LIMSEQ_subseq_LIMSEQ[OF _ mono_f])
show "?e4a \<longlonglongrightarrow> 0"
proof (subst tendsto_norm_zero_iff[symmetric],
unfold norm_mult norm_power large power_one mult_1_right norm_divide norm_of_real
tendsto_rabs_zero_iff)
have deg_q: "degree q \<le> m1" unfolding q_def using deg_p[of m1]
by (intro degree_diff_le degree_monom_le, auto)
have coeff_q_m1: "coeff q m1 = 0" unfolding q_def c_def m1_def[symmetric] using deg_p[of m1] by simp
from deg_q coeff_q_m1 have "degree q < m1 \<or> q = 0" by fastforce
thus "(\<lambda>n. poly q (?r n) / (c * ?r n ^ m1)) \<longlonglongrightarrow> 0"
proof
assume "degree q < m1"
thus ?thesis unfolding poly_altdef sum_divide_distrib
proof (intro tendsto_null_sum, goal_cases)
case (1 i)
hence "i < m1" by auto
thus ?case using c0 by real_asymp
qed
qed auto
qed
next
have id: "D * x + (m - 1) + off + i - j = D * x + off" for x
unfolding ji[symmetric] ji_def using ij' by auto
from d[OF kla large(1)] have 1: "la ^ d la = 1" by auto
from split_list[OF kla] obtain as bs where n_as: "n_as = as @ (k,la) # bs" by auto
obtain C where D: "D = d la * C" unfolding D_def unfolding n_as using large by auto
show "(?e4b o f off) \<longlonglongrightarrow> e"
unfolding e f_def o_def id
unfolding power_add power_mult D 1 by auto
qed
thus ?thesis by simp
qed
also have "((e2 o f off) \<longlonglongrightarrow> e) = ((?jbc o f off) \<longlonglongrightarrow> e)"
proof (rule tendsto_cong, unfold eventually_at_top_linorder, rule exI[of _ k],
...
...
@@ -493,7 +504,7 @@ proof -
have "(?jbc o f off) \<longlonglongrightarrow> e" .
} note part2 = this
from part1 part2 have "(?jbc o f off) \<longlonglongrightarrow> e" by linarith
thus ?thesis unfolding e_def o_def C_def
.
thus ?thesis unfolding e_def o_def C_def
by (simp add: field_simps)
qed
definition lambda where "lambda i = snd (n_as ! fst (j_to_jb_index n_as i))"
...
...
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