Re: MISC: Internet Media Type registration: proposed TAG finding

From: Dan Connolly <connolly@w3.org>
Subject: Re: MISC: Internet Media Type registration: proposed TAG finding
Date: 30 May 2002 09:05:20 -0500

> On Thu, 2002-05-30 at 08:28, Peter F. Patel-Schneider wrote:
> > From: Dan Connolly <connolly@w3.org>
> > Subject: Re: MISC: Internet Media Type registration: proposed TAG finding
> > Date: 29 May 2002 20:27:11 -0500
> > 
> > > On Fri, 2002-05-24 at 23:05, Peter F. Patel-Schneider wrote:
> > 
> > [...]
> > 
> > > > But according to your rules, any method of providing meaning for this
> > > > extension is adequate.
> > > 
> > > No, only those that are monotonic. i.e. when you specify an extension,
> > > you can only throw out models; you can't put any back in.
> > > 
> > > >  OK, the method that I will use is that it means
> > > > what I mean it to mean.  
> > > 
> > > So long as it's monotonic, then you haven't provided an example
> > > that ...
> > 
> > Suppose we have 
> > 
> > <ex:John> <ex:loves> <ex:Mary> .
> > 
> > <_:s1> <rdf:type> <rdf:Statement> .
> > <_:s1> <rdf:subject> <var:?x> .
> > <_:s1> <rdf:predicate> <ex:loves> .
> > <_:s1> <rdf:object> <var:?y> .
> > 
> > <_:s2> <rdf:type> <rdf:Statement> .
> > <_:s2> <rdf:subject> <var:?a> .
> > <_:s2> <rdf:predicate> <var:?b> .
> > <_:s2> <rdf:object> <var:?c> .
> > 
> > <_:s1> <log:implies> <_:s2> .
> > 
> > The non-RDF part of this document, i.e., the meaning of log:implies as a
> > form of logical implication, completely changes the meaning of foo:loves.
> 
> No, there are no more models in a theory that include a
> specification of log:implies than there are in a theory
> that just treats log:implies as a plain RDF predicate.
> 
> I'm not sure what you mean by "the meaning of <a term>",
> nor "completely changes the meaning of <a term>".
> 
> Going back a bit to your message of 23 May 2002 20:14:13 -0400,
> you said:
> 
> PFPS> so the partial understanding may not be related to the ``real''
> PFPS> meaning in any worthwhile fashion.
> 
> to which I replied, 23 May 2002 22:08:16 -0500:
> 
> DC> it's monotonic, in that the more you understand, the fewer
> DC> interpretations are models. You can't rule out models by
> DC> failing to understand something.
> 
> The example above is not a counterexample of this claim
> that partial understanding is monotonic.

So you claim.   

The RDF meaning of log:implies includes lots of interpretations where the
implication does not hold.  The extended meaning incorporates only those
where the implication does hold.  This completely changes the meaning of
log:implies, changing it from an uninterpreted property to a logical
connective.

> -- 
> Dan Connolly, W3C http://www.w3.org/People/Connolly/

Peter F. Patel-Schneider

Received on Thursday, 30 May 2002 11:04:14 UTC