W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > August 2001

layering RDFS in the MT [was: New RDF model theory]

From: Dan Connolly <connolly@w3.org>
Date: Wed, 15 Aug 2001 21:17:44 -0500
Message-ID: <3B7B2D48.323EDA5F@w3.org>
To: pat hayes <phayes@ai.uwf.edu>
CC: w3c-rdfcore-wg@w3.org
pat hayes wrote:
[...]
> I will try to get the damn thing completely done, except for the
> Proofs appendix, by the end of the week, at which point it should be
> puttable on a website. (Also I could re-do the powerpoint slides to
> fit this new version if y'all think that would be useful.)
> 
> Any feedback welcome.

[...]

>                                     Name: RDF_Model_Theory_postF2F.html

| <comment> When considering RDFS  we will require interpretations
| to have extra structure. </comment> 

I'd rather not take that approach. I'd rather that the model
theory were a model theory for all of RDF, no more, and no less.
I don't want to give the impression that folks should tinker
with the core model theory when they introduce new vocabulary.

New vocabularies should just be specified as constraints
on the core interpretation structure, not changes to it.


| in particujlar, the notion of a 'class', so we will need to
| assume that the universe of
| interpretations contains classes as elements. 

Why? It seems to me that IEXT(rdf:type) completely captures
the notion of 'class'. Anything we want to say about 'class'
can be said by way of IEXT(rdf:type), no?

| 5. A subset IC of IR, containing classes

| 6.  A mapping ICEXT  from IC to  the powerset of (IR union LV) ,
| ie the set of subsets of elements
| of IR or  XL.

ICEXT(c) is just the set { x: <x,c> \in IEXT(rdf:type) }, no?
an IC is (at least) the set { y: exists x where <x,y> \in IEXT(rdf:type)
}
right?

yup... you say as much later in the document:

| >> <x,y> is in IEXT(I(rdf:type)) iff x is in ICEXT(y)


-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Wednesday, 15 August 2001 22:17:46 EDT

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