diff -r 74e8f703f5f2 -r cf6ad8d22793 src/HOL/Isar_examples/Peirce.thy --- a/src/HOL/Isar_examples/Peirce.thy Fri May 28 11:42:07 1999 +0200 +++ b/src/HOL/Isar_examples/Peirce.thy Fri May 28 13:30:59 1999 +0200 @@ -1,12 +1,11 @@ (* Title: HOL/Isar_examples/Peirce.thy ID: $Id$ Author: Markus Wenzel, TU Muenchen - -Peirce's law: examples of classical proof. *) theory Peirce = Main:; +text {* Peirce's law: examples of classical proof. *}; theorem "((A --> B) --> A) --> A"; proof;