src/HOL/Arith.thy
1996-02-05 ago expanded tabs; renamed subtype to typedef;
1995-11-29 ago removed quotes from types in consts and syntax sections
1995-03-24 ago changed syntax of tuples from <..., ...> to (..., ...)
1995-03-20 ago changed syntax of "if"
1995-03-03 ago new version of HOL with curried function application