Attic/Prelude.thy
author urbanc
Thu, 09 Feb 2012 13:05:51 +0000
changeset 287 440382eb6427
parent 170 b1258b7d2789
permissions -rw-r--r--
more on the specification section

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