ery expressive language, but it was developed by a person who did
not have a formal logic bent, so it has nothing approaching the kind of solid
formal foundation that KIF does.  It would no doubt be possible to put EXPRESS
on such a foundation - which would presumably require making some changes to
it.

EXPRESS also had different purpose than KIF did. It is designed to express data
models, not knowledge per se.  This is not to suggest that there is something
intrinsically different about a data model and a 