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Re: Converting SHOE to RDF: about 2/3 done; some gotchas

From: Dan Connolly <connolly@w3.org>
Date: Fri, 12 May 2000 17:40:36 -0500
Message-ID: <391C8864.C049AD2B@w3.org>
To: Jeff Heflin <heflin@cs.umd.edu>
CC: www-rdf-interest@w3.org
Jeff Heflin wrote:
> 
> Hi all,
> 
> As the main spokesperson for SHOE I though I'd comment on Dan's post.

Thanks!

I hope to respond in substance eventually; just a few
quick points for now...

[...]

> Second, SHOE use-ontology statements are similar to the way RDF use
> namespaces to identify schemas. I say similar and not equivalent because
> a use-ontology says that I specifically agree only to the semantics
> implied by this ontology and those ontologies which it extends. It's not
> clear that RDF Schema has such a feature. For example if you have a
> schema http://schema.org/web which defines the class Web_Developer, what
> does it mean when someone else creates another schema (say
> http://hacker.org/hah) that includes the following RDF:
> 
> <rdfs:Class rdf:about="http://schema.org/web#Web_Developer">
>   <rdfs:subclassOf rdf:resource="#Silly_Person">
> </rdfs:Class>
> 
> I do not see any restrictions in the RDFS spec to prevent such a
> statement.

Why should we prevent such a statement? Anyone can say anything
about anything, no?

cf

Saying anything about anything: Comments on Harle & Fensel Tim
Berners-Lee
     (Tue, Dec 21 1999) 
http://lists.w3.org/Archives/Public/www-rdf-interest/1999Dec/0113.html


> Also, as I understand it way namespaces are used in RDF is
> only to uniquely identify what object you're talking about, not which
> sets of definitions you subscribe to. Thus, if I state that I am
> Web_Developer, then do I also imply that I am a Silly_Person?

If you say P and P->Q, then you imply Q, yes. But
if you say P and somebody else says P->Q, then a third
party may or may not decide to trust you both enough
to conclude Q.


> Note that
> in SHOE, you cannot state that a class defined elsewhere is the subclass
> of another class, and even if you could, the semantics for reasoning
> about web pages are those that the web page explicitly commits to. As an
> aside, we have worked out a formal model that deals with intended
> perspectives (what the author explictly believes can be reasoned from
> his web page) and alternate perspectives (what the user wants to
> conclude from a web page). These issues are discussed in a paper that
> will appear in the Seventeenth National Conference on Artificial
> Intelligence (AAAI-2000). The paper is available online from
> http://www.cs.umd.edu/projects/plus/SHOE/pubs/#aaai2000.


Thanks for the reference... oh for more time to read all the
nifty stuff around here!


> BTW: Dan, some of the links on your SHOE to RDF page appear to be
> broken, or at least not available to the public. In particular the tidy
> configuration, RDF output, and xhtmlized PLUS page.

Oops... sorry... hmm... I'm having trouble fixing that.



-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Friday, 12 May 2000 18:40:17 GMT

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