# HG changeset patch # User paulson # Date 1085735955 -7200 # Node ID 4b2c006d053477cabe747331874aefeb6ace347e # Parent 9144ec118703269f104e26210536ce7ff71d3e78 new theorem Collect_imp_eq diff -r 9144ec118703 -r 4b2c006d0534 src/HOL/Set.thy --- a/src/HOL/Set.thy Wed May 26 19:06:09 2004 +0200 +++ b/src/HOL/Set.thy Fri May 28 11:19:15 2004 +0200 @@ -1108,6 +1108,9 @@ lemma Collect_disj_eq: "{x. P x | Q x} = {x. P x} \ {x. Q x}" by blast +lemma Collect_imp_eq: "{x. P x --> Q x} = -{x. P x} \ {x. Q x}" + by blast + lemma Collect_conj_eq: "{x. P x & Q x} = {x. P x} \ {x. Q x}" by blast