diff -r c1262feb61c7 -r 3edd5f813f01 src/HOL/Isar_examples/Peirce.thy --- a/src/HOL/Isar_examples/Peirce.thy Mon Jun 22 22:51:08 2009 +0200 +++ b/src/HOL/Isar_examples/Peirce.thy Mon Jun 22 23:48:24 2009 +0200 @@ -1,11 +1,12 @@ (* Title: HOL/Isar_examples/Peirce.thy - ID: $Id$ Author: Markus Wenzel, TU Muenchen *) header {* Peirce's Law *} -theory Peirce imports Main begin +theory Peirce +imports Main +begin text {* We consider Peirce's Law: $((A \impl B) \impl A) \impl A$. This is