Prelude.thy
author urbanc
Fri, 11 Feb 2011 13:30:37 +0000
changeset 98 36f9d19be0e6
parent 35 d2ddce8b36fd
permissions -rw-r--r--
included comments by Xingyuan

theory Prelude
imports Main
begin

(*
To make the theory work under Isabelle 2009 and 2011

Isabelle 2009: set_ext
Isabelle 2011: set_eqI

*)


lemma set_eq_intro:
  "(\<And>x. (x \<in> A) = (x \<in> B)) \<Longrightarrow> A = B"
by blast


end