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Re: SEM DESIDERATA: my initial desiderata list

From: Lynn Andrea Stein <lynn.stein@olin.edu>
Date: Fri, 15 Mar 2002 11:23:00 -0500
Message-ID: <3C921FE3.549AF286@olin.edu>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
CC: WebOnt WG <www-webont-wg@w3.org>
Several questions/clarifications:


In http://lists.w3.org/Archives/Public/www-webont-wg/2002Mar/0173.html, "Peter
F. Patel-Schneider" wrote:

>                 Potential Desiderata for the Web Ontology Language

I (LAS) include only those potential desiderata on which I have something to
say/ask.

> Syntax:
>
> 1/ Syntax is (equivalent to) n-triples (i.e., RDF syntax).
>    All syntax (except, maybe, datatypes) is carried in triples.

Pretty clearly we will need *some* sort of (unordered) listing/grouping
construct that is bounded, i.e., defines a list/group containing *exactly* the
listed/grouped elements.  daml:collection was one attempt to provide such a
thing.  I don't believe we can avoid having such a thing.  (BTW, I also
believe that adding such a thing to RDF's semantics may cause problems as it
essentially introduces negation.  Pat?)

> Semantics:
>
> 1/ There is a model-theoretic semantics, compatible with the RDF(S)
> model-theoretic semantics.
>    All triples are assertions.

As we discussed, this is one several of us want to question.  But this is only
a potential desiderata list....

>    All URIs denote elements of the domain of discourse.

This doesn't make them real, of course, but yes, they should denote
"discussable" things; they are names after all.  (But we have to be careful
about what it means to talk about unicorns....  forall x. (x a unicorn) -> (!
exists x)......(or, in pseudo-n3,
this log:forAll :x. {:x a :unicorn} log:implies {log:not {log:exists :x}}.

>    All classes are elements of the domain of discourse.

I'm not sure what this means.  Does this mean all classes mentioned?  All
classes conceivable?  All classes describable (in some language)?  The class
of all classes that do not include themselves as members?  I'm not trying to
be difficult, just clear that we're on the same page.

>    All properties are elements of the domain of discourse.

Ditto

> 2/ Inference is standard entailment in the model theory.

Not, for example, intuitionistic entailment (cf.
http://plato.stanford.edu/entries/logic-intuitionistic/ or
http://www.xrefer.com/entry/552450)?

> Classes:
>
> 1/ A way to create / query complex properties is via a defined class, e.g.,
>    the intersection of a and b, the union of a and b, objects who have at
>    least one child.

I am not sure that this use of "defined classes" is the same as what I thought
DLs meant by defined classes.  Could you clarify?

> I'm willing to keep this list up to date and to incorporate other
> desiderata into the list.

Thanks!

Lynn Andrea Stein
Received on Friday, 15 March 2002 11:23:07 GMT

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