src/HOL/Probability/Borel_Space.thy
changeset 44928 7ef6505bde7f
parent 44890 22f665a2e91c
child 45287 97df8c08291c
equal deleted inserted replaced
44927:8bf41f8cf71d 44928:7ef6505bde7f
  1412   shows "(\<lambda>x. SUP i : A. f i x) \<in> borel_measurable M" (is "?sup \<in> borel_measurable M")
  1412   shows "(\<lambda>x. SUP i : A. f i x) \<in> borel_measurable M" (is "?sup \<in> borel_measurable M")
  1413   unfolding borel_measurable_ereal_iff_ge
  1413   unfolding borel_measurable_ereal_iff_ge
  1414 proof
  1414 proof
  1415   fix a
  1415   fix a
  1416   have "?sup -` {a<..} \<inter> space M = (\<Union>i\<in>A. {x\<in>space M. a < f i x})"
  1416   have "?sup -` {a<..} \<inter> space M = (\<Union>i\<in>A. {x\<in>space M. a < f i x})"
  1417     by (auto simp: less_SUP_iff SUPR_apply)
  1417     by (auto simp: less_SUP_iff SUP_apply)
  1418   then show "?sup -` {a<..} \<inter> space M \<in> sets M"
  1418   then show "?sup -` {a<..} \<inter> space M \<in> sets M"
  1419     using assms by auto
  1419     using assms by auto
  1420 qed
  1420 qed
  1421 
  1421 
  1422 lemma (in sigma_algebra) borel_measurable_INF[simp, intro]:
  1422 lemma (in sigma_algebra) borel_measurable_INF[simp, intro]:
  1425   shows "(\<lambda>x. INF i : A. f i x) \<in> borel_measurable M" (is "?inf \<in> borel_measurable M")
  1425   shows "(\<lambda>x. INF i : A. f i x) \<in> borel_measurable M" (is "?inf \<in> borel_measurable M")
  1426   unfolding borel_measurable_ereal_iff_less
  1426   unfolding borel_measurable_ereal_iff_less
  1427 proof
  1427 proof
  1428   fix a
  1428   fix a
  1429   have "?inf -` {..<a} \<inter> space M = (\<Union>i\<in>A. {x\<in>space M. f i x < a})"
  1429   have "?inf -` {..<a} \<inter> space M = (\<Union>i\<in>A. {x\<in>space M. f i x < a})"
  1430     by (auto simp: INF_less_iff INFI_apply)
  1430     by (auto simp: INF_less_iff INF_apply)
  1431   then show "?inf -` {..<a} \<inter> space M \<in> sets M"
  1431   then show "?inf -` {..<a} \<inter> space M \<in> sets M"
  1432     using assms by auto
  1432     using assms by auto
  1433 qed
  1433 qed
  1434 
  1434 
  1435 lemma (in sigma_algebra) borel_measurable_liminf[simp, intro]:
  1435 lemma (in sigma_algebra) borel_measurable_liminf[simp, intro]: