add lemmas INF_image, SUP_image
authorhuffman
Mon, 08 Aug 2011 11:47:41 -0700
changeset 44068 dc0a73004c94
parent 44067 5feac96f0e78
child 44069 d7c7ec248ef0
child 44072 5b970711fb39
add lemmas INF_image, SUP_image
src/HOL/Complete_Lattice.thy
--- a/src/HOL/Complete_Lattice.thy	Mon Aug 08 11:25:18 2011 -0700
+++ b/src/HOL/Complete_Lattice.thy	Mon Aug 08 11:47:41 2011 -0700
@@ -172,6 +172,12 @@
 lemma SUP_insert: "(\<Squnion>x\<in>insert a A. f x) = f a \<squnion> SUPR A f"
   by (simp add: SUP_def Sup_insert)
 
+lemma INF_image: "(\<Sqinter>x\<in>f`A. g x) = (\<Sqinter>x\<in>A. g (f x))"
+  by (simp add: INF_def image_image)
+
+lemma SUP_image: "(\<Squnion>x\<in>f`A. g x) = (\<Squnion>x\<in>A. g (f x))"
+  by (simp add: SUP_def image_image)
+
 lemma Inf_Sup: "\<Sqinter>A = \<Squnion>{b. \<forall>a \<in> A. b \<sqsubseteq> a}"
   by (auto intro: antisym Inf_lower Inf_greatest Sup_upper Sup_least)