- From: Dan Connolly <connolly@w3.org>
- Date: 30 May 2002 16:57:28 -0500
- To: patrick hayes <phayes@ai.uwf.edu>
- Cc: www-rdf-logic@w3.org
On Wed, 2002-05-29 at 11:35, patrick hayes wrote: [...] > >It wouldn't be unprecedented, by the way: > > > > http://www.w3.org/2000/10/swap/log#Truth > > Wow, scales fall from my eyes! Why is this so crazy? It doesn't seem interestingly different from wtr in KIF. [...] > Seriously, that document (1) does not define logical truth in any way > whatsoever (2) says this: - <rdfs:Class > rdf:about="http://www.w3.org/2000/10/swap/log#Truth"> > <rdfs:comment>Something which is true: belive it as you would > belive this. Understood natively by cwm in that it will execute rules > in a formula declared a Truth within a formula it is already taking > rules from.</rdfs:comment> > > which seems to indicate that log#Truth in fact is simply supposed to > mean 'asserted', which is perfectly meaningful, but is not the same > as 'logically true'. Er... close to that; it's a de-quoting mechanism. > And in fact, the document does not define *any* > meanings in RDF, or constrain the RDF interpretations, in any way > whatsoever. It is just English with RDF decorations added. (The CWM > code might be said to be a kind of implicit machine-readable > constraint on interpretations of this vocabulary - along the lines of > 'this means whatever it takes to make CWM produce valid conclusions' > - but it goes well beyond what an RDF engine would be able to make > use of.) [...] > >> Who discovers this, and how? > > > >As explained above, I (i.e. anybody using > >the framework) use the deployed URI infrastructure > >to dereference http://www.daml.org/2001/03/daml+oil#UniqueProperty > >and I see: > > > ><rdfs:Class rdf:ID="UniqueProperty"> > > <rdfs:label>UniqueProperty</rdfs:label> > > <rdfs:comment> > > compare with maxCardinality=1; e.g. integer successor: > > if P is a UniqueProperty, then if P(x, y) and P(x, z) then y=z. > > cf OIL FunctionalProperty. > > </rdfs:comment> > > <rdfs:subClassOf > >rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Property"/> > ></rdfs:Class> > > > >The comment there is reasonably clear as a constraint > >on interpretations, no? > > NO!!! It is not in any way a constraint on interpretations, any more > than a comment in a program is code. How is that not acceptable as a constraint on interpretations, but stuff like this is? [[ for ?D an XML Schema datatype, IO(?O) is the singleton set containing the element of IC(?D) that has lexical representation ?L, provided that there is one, otherwise IO(?O) = { } ]] -- http://www.w3.org/TR/2001/NOTE-daml+oil-model-20011218#3 > A comment is a COMMENT, and that > is all. YOU can read that and understand it, Dan, because you are a > HUMAN BEING WHO UNDERSTANDS ENGLISH. The whole point of the semantic > web is to allow SOFTWARE AGENTS to do a little understanding. Yes, so, I read the comment and write some code. > When > you can write a Perl script that can figure out the content of the > English comments, then maybe you can claim that the meaning of the > comments is part of the meaning of the formalism. It still wouldn't > be part of RDF, but you could call it RDFE . It seems to me to be a perfectly reasonable part of the Resource Description Framework. I guess I'm willing to call it an extension to RDF, if that makes you happy. But it seems pretty arbitrary, to me. [...] > >Let's put it this way: does dublin core fit into the framework? > >Or is RDF+dc an extension? How about a document that > >uses RDFS, DAML+OIL, and dublin core together? Is that > >another sort of extension? > > Dan, you cannot possibly be this obtuse. Surely you know the > distinction between a language and a set of axioms in that language. > DC is a set of assertions in RDF, right? No; it's a set of terms defined by a community of practice. There are semantics to the dublin core terms that aren't written in the RDF specs. > That means that one can > interpret those DC assertions using the RDF semantics and they mean > something that approximates to what the DC writers had in mind, > roughly. If you do that to DAML, you often *don't * get an > approximation of what the writer of the DAML had in mind. I must be quite obtuse; I don't see any fundamental difference between partial understanding of DC semantics and partial understanding of DAML semantics. -- Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Thursday, 30 May 2002 18:20:57 UTC