--- a/src/HOL/Multivariate_Analysis/Integral_Test.thy Thu Aug 04 18:45:28 2016 +0200
+++ b/src/HOL/Multivariate_Analysis/Integral_Test.thy Thu Aug 04 19:36:31 2016 +0200
@@ -1,18 +1,18 @@
(* Title: HOL/Multivariate_Analysis/Integral_Test.thy
Author: Manuel Eberl, TU München
*)
-
+
section \<open>Integral Test for Summability\<close>
theory Integral_Test
-imports Integration
+imports Henstock_Kurzweil_Integration
begin
text \<open>
- The integral test for summability. We show here that for a decreasing non-negative
- function, the infinite sum over that function evaluated at the natural numbers
+ The integral test for summability. We show here that for a decreasing non-negative
+ function, the infinite sum over that function evaluated at the natural numbers
converges iff the corresponding integral converges.
-
+
As a useful side result, we also provide some results on the difference between
the integral and the partial sum. (This is useful e.g. for the definition of the
Euler-Mascheroni constant)
@@ -33,7 +33,7 @@
proof -
note int = integrable_continuous_real[OF continuous_on_subset[OF cont]]
let ?int = "\<lambda>a b. integral {of_nat a..of_nat b} f"
- have "-sum_integral_diff_series n = ?int 0 n - (\<Sum>k\<le>n. f (of_nat k))"
+ have "-sum_integral_diff_series n = ?int 0 n - (\<Sum>k\<le>n. f (of_nat k))"
by (simp add: sum_integral_diff_series_def)
also have "?int 0 n = (\<Sum>k<n. ?int k (Suc k))"
proof (induction n)
@@ -60,7 +60,7 @@
have d_mono: "sum_integral_diff_series (Suc n) \<le> sum_integral_diff_series n" for n
proof -
fix n :: nat
- have "sum_integral_diff_series (Suc n) - sum_integral_diff_series n =
+ have "sum_integral_diff_series (Suc n) - sum_integral_diff_series n =
f (of_nat (Suc n)) + (?int 0 n - ?int 0 (Suc n))"
unfolding sum_integral_diff_series_def by (simp add: algebra_simps)
also have "?int 0 n - ?int 0 (Suc n) = -?int n (Suc n)"
@@ -77,7 +77,7 @@
lemma sum_integral_diff_series_Bseq: "Bseq sum_integral_diff_series"
proof -
- from sum_integral_diff_series_nonneg and sum_integral_diff_series_antimono
+ from sum_integral_diff_series_nonneg and sum_integral_diff_series_antimono
have "norm (sum_integral_diff_series n) \<le> sum_integral_diff_series 0" for n by simp
thus "Bseq sum_integral_diff_series" by (rule BseqI')
qed
@@ -97,12 +97,12 @@
also have "... \<longleftrightarrow> convergent (\<lambda>n. integral {0..of_nat n} f)"
proof
assume "convergent (\<lambda>n. \<Sum>k\<le>n. f (of_nat k))"
- from convergent_diff[OF this sum_integral_diff_series_convergent]
- show "convergent (\<lambda>n. integral {0..of_nat n} f)"
+ from convergent_diff[OF this sum_integral_diff_series_convergent]
+ show "convergent (\<lambda>n. integral {0..of_nat n} f)"
unfolding sum_integral_diff_series_def by simp
next
assume "convergent (\<lambda>n. integral {0..of_nat n} f)"
- from convergent_add[OF this sum_integral_diff_series_convergent]
+ from convergent_add[OF this sum_integral_diff_series_convergent]
show "convergent (\<lambda>n. \<Sum>k\<le>n. f (of_nat k))" unfolding sum_integral_diff_series_def by simp
qed
finally show ?thesis by simp