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Added strong congruence rule for UN.
authorberghofe
Thu, 29 Jan 2009 22:28:03 +0100
changeset 29691 9f03b5f847cd
parent 29690 c81f8b2967e1
child 29692 121289b1ae27
Added strong congruence rule for UN.
src/HOL/Set.thy file | annotate | diff | comparison | revisions 
--- a/src/HOL/Set.thy	Thu Jan 29 22:27:07 2009 +0100
+++ b/src/HOL/Set.thy	Thu Jan 29 22:28:03 2009 +0100
@@ -885,6 +885,10 @@
     "A = B ==> (!!x. x:B ==> C x = D x) ==> (UN x:A. C x) = (UN x:B. D x)"
   by (simp add: UNION_def)
 
+lemma strong_UN_cong:
+    "A = B ==> (!!x. x:B =simp=> C x = D x) ==> (UN x:A. C x) = (UN x:B. D x)"
+  by (simp add: UNION_def simp_implies_def)
+
 
 subsubsection {* Intersections of families *}
isabelle