2013-05-07 traytel 2013-05-07 got rid of the set based relator---use (binary) predicate based relator instead
2013-03-18 traytel 2013-03-18 eliminate duplicated constant (diag vs. Id_on)
2012-11-13 traytel 2012-11-13 import Sublist rather than PrefixOrder to avoid unnecessary class instantiation
2012-09-21 blanchet 2012-09-21 renamed "Codatatype" directory "BNF" (and corresponding session) -- this opens the door to no-nonsense session names like "HOL-BNF-LFP"