Re: What do the ontologists want

From: Sergey Melnik <melnik@db.stanford.edu>
Subject: Re: What do the ontologists want
Date: Wed, 30 May 2001 18:58:43 -0700

> "Peter F. Patel-Schneider" wrote:
> > 
> > In defense of stripped-down RDF, there is nothing technically wrong with a
> > logical formalism that can represent only positive ground triples.  Such a
> > formalism can certainly convey some useful semantic information.
> > 
> > It is just that such a representation formalism cannot be used to
> > *represent* anything more than positive ground triples.  Using positive
> > ground triples to encode a more-expressive formalism requires encoding, which
> > requires a new semantics, defined on top of the semantics for the positive
> > ground triples, and makes it essentially impossible to use the semantics
> > for the positive ground triples to represent domain information.
> 
> Is that true indeed? If a logical formula is encoded as a set of
> statements, wouldn't it be possible to find an interpretation that maps
> the corresponding resources into the domain of discourse, which contains
> people, Web sites, logical formulae and classes?

Sure, you could have an RDF ``predicate'' for disjunction and one for
negation, etc., etc.  However, there is no connection between the RDF
predicates and disjunction or negation within RDF, and this mapping is
precisely what I meant by a new semantics.

> Wrt the latter: it is absolutely necessary to map resources that
> represent classes onto sets of objects in the domain of discourse (D)?
> Would it be possible to map such resources to elements of D that
> represent classes and have certain relationships with their members?

Sure, this can be done, but this is completely irrelevant to the encoding
issue.

> Sorry if the questions don't make sense - I'm not a logician.
> 
> Best,
> Sergey

peter