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Re: semantics of daml:equivalentTo [was: Comments on Annotated DAML 1.6]

From: pat hayes <phayes@ai.uwf.edu>
Date: Fri, 13 Oct 2000 14:12:34 -0500
Message-Id: <v04210108b60d08ff21e0@[205.160.76.86]>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: www-rdf-logic@w3.org
>From: pat hayes <phayes@ai.uwf.edu>
>Subject: Re: semantics of daml:equivalentTo [was: Comments on 
>Annotated    DAML   1.6]
>Date: Fri, 13 Oct 2000 12:00:45 -0500
>
> > >From: Jeff Heflin <heflin@cs.umd.edu>
> > >Subject: Re: semantics of daml:equivalentTo [was: Comments on
> > >Annotated  DAML   1.6]
> > >Date: Thu, 12 Oct 2000 15:29:56 -0400
> > >
> > > > I'd just like to elaborate on Jim's message. I believe that 
>equivalentTo
> > > > is the DAML version of the SHOE <DEF-RENAME> element. In SHOE,
> > > > DEF-RENAME allows an ontology to provide an alias for a term defined
> > > > elsewhere. Essentially, it means that both terms reference the same
> > > > concept, and thus any assertion that is made using one term 
>is also true
> > > > if the other term was substituted in its place. This is really easy to
> > > > implement: you keep a hash table that matches aliases with the base
> > > > terms (used in the original definitions) that they renamed, and upon
> > > > parsing a document or issuing a query you can perform the necessary
> > > > substitutions to rephrase it in only base terms.
> > > > Jeff
>
> > There is
> > a reasonably well-defined meaning for equality (=identity =
> > equivalence) which is pretty much what Jeff says above: it means that
> > the terms refer to the same thing. So to assert
> >   equivalentTo(X, Y)
> > is to claim that X and Y have the same denotation. Now, this in turn
> > is just as clear or as murky as the notion of denotation is for X and
> > Y.
> >
> > Pat Hayes
>
>It is my belief that Jeff's belief is that equivalentTO should be much more
>like the other option I outlined, namely that X is given the definition
>that Y has and that X can have no other definition.

Yes, but the distinction between this version and a simple assertion 
of equality lies in what might called the definitional force rather 
than the propositional content. I agree that this is important, even 
central, for DAML in the long run, but in the short run I'd like to 
get the simple stuff clearly defined.

BTW, I think that what Jeff really, really means is something like 
your 'strong' option, but restricted to one webpage. So it is strong 
but also 'local'. However I confess that I really have no clear idea 
what this actually means.

Pat

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Received on Friday, 13 October 2000 15:09:45 GMT

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