src/HOL/Probability/Measure.thy
changeset 44890 22f665a2e91c
parent 43920 cedb5cb948fd
child 44928 7ef6505bde7f
equal deleted inserted replaced
44889:340df9f3491f 44890:22f665a2e91c
   938     using sigma_finite by auto
   938     using sigma_finite by auto
   939   then show ?thesis
   939   then show ?thesis
   940   proof (intro exI[of _ "\<lambda>n. \<Union>i\<le>n. F i"] conjI allI)
   940   proof (intro exI[of _ "\<lambda>n. \<Union>i\<le>n. F i"] conjI allI)
   941     from F have "\<And>x. x \<in> space M \<Longrightarrow> \<exists>i. x \<in> F i" by auto
   941     from F have "\<And>x. x \<in> space M \<Longrightarrow> \<exists>i. x \<in> F i" by auto
   942     then show "(\<Union>n. \<Union> i\<le>n. F i) = space M"
   942     then show "(\<Union>n. \<Union> i\<le>n. F i) = space M"
   943       using F by fastsimp
   943       using F by fastforce
   944   next
   944   next
   945     fix n
   945     fix n
   946     have "\<mu> (\<Union> i\<le>n. F i) \<le> (\<Sum>i\<le>n. \<mu> (F i))" using F
   946     have "\<mu> (\<Union> i\<le>n. F i) \<le> (\<Sum>i\<le>n. \<mu> (F i))" using F
   947       by (auto intro!: measure_finitely_subadditive)
   947       by (auto intro!: measure_finitely_subadditive)
   948     also have "\<dots> < \<infinity>"
   948     also have "\<dots> < \<infinity>"