2011-10-28 ago slightly more explicit/syntactic modelling of morphisms;
2010-05-31 ago modernized some structure names, keeping a few legacy aliases;
2009-01-21 ago eliminated obsolete var morphism;
2009-01-21 ago binding is alias for Binding.T
2008-12-04 ago cleaned up binding module and related code
2008-09-02 ago name/var morphism operates on Name.binding;
2007-07-28 ago type Morphism.declaration;
2007-04-14 ago added Morphism.transform/form (generic non-sense);
2007-04-03 ago renamed comp to compose (avoid clash with Alice keywords);
2007-02-04 ago added cterm interface;
2006-11-24 ago simultaneous fact morphism;
2006-11-23 ago added name/var/typ/term/thm_morphism;
2006-11-23 ago Abstract morphisms on formal entities.