src/HOL/SEQ.thy
changeset 31017 2c227493ea56
parent 30730 4d3565f2cb0e
child 31336 e17f13cd1280
equal deleted inserted replaced
31016:e1309df633c6 31017:2c227493ea56
   485   fixes a b :: "'a::real_normed_field"
   485   fixes a b :: "'a::real_normed_field"
   486   shows "\<lbrakk>X ----> a; Y ----> b; b \<noteq> 0\<rbrakk> \<Longrightarrow> (\<lambda>n. X n / Y n) ----> a / b"
   486   shows "\<lbrakk>X ----> a; Y ----> b; b \<noteq> 0\<rbrakk> \<Longrightarrow> (\<lambda>n. X n / Y n) ----> a / b"
   487 by (simp add: LIMSEQ_mult LIMSEQ_inverse divide_inverse)
   487 by (simp add: LIMSEQ_mult LIMSEQ_inverse divide_inverse)
   488 
   488 
   489 lemma LIMSEQ_pow:
   489 lemma LIMSEQ_pow:
   490   fixes a :: "'a::{real_normed_algebra,recpower}"
   490   fixes a :: "'a::{power, real_normed_algebra}"
   491   shows "X ----> a \<Longrightarrow> (\<lambda>n. (X n) ^ m) ----> a ^ m"
   491   shows "X ----> a \<Longrightarrow> (\<lambda>n. (X n) ^ m) ----> a ^ m"
   492 by (induct m) (simp_all add: LIMSEQ_const LIMSEQ_mult)
   492 by (induct m) (simp_all add: LIMSEQ_const LIMSEQ_mult)
   493 
   493 
   494 lemma LIMSEQ_setsum:
   494 lemma LIMSEQ_setsum:
   495   assumes n: "\<And>n. n \<in> S \<Longrightarrow> X n ----> L n"
   495   assumes n: "\<And>n. n \<in> S \<Longrightarrow> X n ----> L n"
  1392     by (rule LIMSEQ_inverse_realpow_zero)
  1392     by (rule LIMSEQ_inverse_realpow_zero)
  1393   thus ?thesis by (simp add: power_inverse)
  1393   thus ?thesis by (simp add: power_inverse)
  1394 qed
  1394 qed
  1395 
  1395 
  1396 lemma LIMSEQ_power_zero:
  1396 lemma LIMSEQ_power_zero:
  1397   fixes x :: "'a::{real_normed_algebra_1,recpower}"
  1397   fixes x :: "'a::{real_normed_algebra_1}"
  1398   shows "norm x < 1 \<Longrightarrow> (\<lambda>n. x ^ n) ----> 0"
  1398   shows "norm x < 1 \<Longrightarrow> (\<lambda>n. x ^ n) ----> 0"
  1399 apply (drule LIMSEQ_realpow_zero [OF norm_ge_zero])
  1399 apply (drule LIMSEQ_realpow_zero [OF norm_ge_zero])
  1400 apply (simp only: LIMSEQ_Zseq_iff, erule Zseq_le)
  1400 apply (simp only: LIMSEQ_Zseq_iff, erule Zseq_le)
  1401 apply (simp add: power_abs norm_power_ineq)
  1401 apply (simp add: power_abs norm_power_ineq)
  1402 done
  1402 done