src/FOLP/ex/If.thy
2008-01-27 wenzelm 2008-01-27 eliminated some legacy ML files;
2006-06-06 wenzelm 2006-06-06 quoted "if";
2005-09-18 wenzelm 2005-09-18 converted to Isar theory format;
1993-09-16 clasohm 1993-09-16 Initial revision