- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Tue, 27 Aug 2002 12:31:37 -0400 (EDT)
- To: seth@robustai.net
- Cc: sandro@w3.org, www-rdf-interest@w3.org
From: "Seth Russell" <seth@robustai.net> Subject: Re: Layering LX (or FOL) on RDF Date: Tue, 27 Aug 2002 09:18:11 -0700 > From: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com> > > > Well, how does one forbid self-referencing sentences. To do so, one would > > have to say something like > > > > _:s rdf:type rdf:Statement . > > _:s rdf:subject _:s . > > > > is not an RDF graph. > > It seems to me that "_:s rdf:subject _:s" is not a self referencing > triple. In fact I dont's see how you could even write a self referencing > triple in RDF at all, since RDF does not even provide for triples to have an > identity. In the example above "_:s" is the identity of the thing of type > Statement, not the identity of the triple. > > Help, I'm confused ? > > Seth Russell Hmm. You have a point here. You would not have to use RDF reification at all. However, suppose you have a way of representing formulae in RDF. This will have to use resources and statements. When you represention ~p, you will have to have an RDF graph with a resource for the formula p and another resource for the formula ~p. How can you allow this, and forbid the RDF graph that is your RDF graph for ~p except that it replaces the resource for p with the resource for ~p? For example, suppose you represent 1/ atomic propositions by resources, 2/ negations as _:x pl:negation y . where y is the resource that represents the negand 3/ conjunctions and disjunctions as _:x pl:conjunction (or pl:disjunction) _:l . _:l rdf:first c1 . _:l rdf:rest _:ll . _:ll rdf:first c2 . _:ll rdf:rest rdf: nil . where c1 and c2 are the components of the conjunction or disjunction. Truth and falsity are represented by inclusion in the classes pl:Truth and pl:Falsity, respectively. To forbid self-reference, you have to *forbid* RDF graphs that contain things like _:x pl:negation _:x . peter
Received on Tuesday, 27 August 2002 12:32:25 UTC