2012-08-22 ago prefer ML_file over old uses;
2012-03-15 ago replacing ":" by "\<in>"
2012-03-06 ago Using mathematical notation for <-> and cardinal arithmetic
2012-03-06 ago mathematical symbols instead of ASCII
2011-12-01 ago renamed inner syntax categories "num" to "num_token" and "xnum" to "xnum_token";
2010-02-13 ago modernized structures;
2010-02-11 ago numeral syntax: clarify parse trees vs. actual terms;
2009-10-17 ago eliminated hard tabulators, guessing at each author's individual tab-width;
2008-03-01 ago tuned ML code, more antiquotations;
2008-02-11 ago Made theory names in ZF disjoint from HOL theory names to allow loading both developments
2007-10-07 ago modernized specifications;
2007-05-31 ago moved Integ files to canonical place;