- From: pat hayes <phayes@ai.uwf.edu>
- Date: Thu, 26 Jul 2001 17:29:43 -0700
- To: Ian Horrocks <horrocks@cs.man.ac.uk>
- Cc: www-rdf-logic@w3.org
>I hope this is the right answer to the right question :-) Yes, thanks. I still have trouble thinking in a Class/restriction way, and this exchange is really only a symptom of that, I suspect. >Ian > >p.s. N&S were useful terms in old style logical KR systems where each >class name had a unique "definition" (i.e., an inclusion or >equivalence axiom with the class name on the l.h.s.). In this context >it made sense to talk about each of these axioms as stating either the >N or N&S conditions for instances of the named class. In modern >systems like D+O, which support arbitrary inclusion/equivalence >axioms, I think talk of N&S conditions is more confusing than >otherwise - I would prefer simply to talk of inclusion (subClassOf) >and equivalence (sameClassAs) axioms. Right, I take your point. BUt the other side of this point is that one can state more than one condition on an thing, and we need to be clear when a given *statement* is intended to be only a constraint on the thing, with possibly others to come, or is intended to lock it down once and for all. This is the sense of "N&S" that I was meaning. Thanks again for your patience. Pat PS. I love the term 'old style logical KR systems', by the way. Ive been in GOFAI for many years, but now it seems Im also in GOFKR. --------------------------------------------------------------------- (650)859 6569 w (650)494 3973 h (until September) phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes
Received on Thursday, 26 July 2001 20:29:33 UTC