- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Mon, 24 Dec 2001 09:07:24 -0500
- To: jos.deroo.jd@belgium.agfa.com
- Cc: www-webont-wg@w3.org
From: jos.deroo.jd@belgium.agfa.com Subject: Re: UPDATE: initial message concerning syntax Date: Mon, 24 Dec 2001 01:28:33 +0100 > > > > One place to see the problem is in KIF. The KIF definition > > > > http://logic.stanford.edu/kif/dpans.html > > > > gives an example where a truth predicate can cause problems. > > > > > > I see > > > > > > > In the DAML+OIL area, if you require the presence of all syntax-like > > > > constructs in the semantics you can easily end up with structures like > > > > > > > > :_x complementOf :_x . > > > > > > > > in all interpretations. Now consider whether :_x is an instance of :_x. > > > > > > I think that complementOf is an irreflexive property > > > How could we express that in SWOL? > > > > > > -- > > > Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/ > > > > SWOL has no such construct. Even if it did, you could construct a > > three-element loop which has the same problem. There are also lots of > > other constructs that cause similar problems. > > ok, so we better simply say that > an odd chain of complementOf is a :schemaInconsistency > i.e. for all :x, :y, :z > > { :x ont:complementOf :y . :y ont:sameClassAs :x } > log:implies { { :x ont:complementOf :y } a :schemaInconsistency } . > > :x ont:sameClassAs :x . > > { :x ont:complementOf :y . :y ont:complementOf :z } > log:implies { :x ont:sameClassAs :z } . OK, you can say this, but what does it mean? log:implies is not defined in RDF, RDFS, DAML+OIL, or SWOL. If you are going to write down syntax, you need to tell your readers how to interpret the syntax. Maybe you are trying to axiomatize DAML+OIL or SWOL. OK, that's fine, but, again, you have to pick some logical formalism to axiomatize it in, and I don't see any indication of which logical formalism to use here. [...] > -- > Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/ Peter F. Patel-Schneider Bell Labs Research
Received on Monday, 24 December 2001 09:09:14 UTC