P.S. Re: Model Theory

It might also be worth adding that in the early days of DAML+OIL the
group wasted a lot of time discussing/arguing about the meaning of
RDFS constructs, such as range and domain, whose semantics was (then)
only informally specified. I would suggest that we don't want to
repeat that mistake with OWL.

Moreover, formalising the semantics of range and domain made it clear
to all concerned that the most obvious reading of the informal
specification had unintended and undesirable consequences. The RDF WG
has since fixed this problem, but they may never have known about it
without the formalisation.

Ian