RE: Literals (Re: model theory for RDF/S)

> -----Original Message-----
> From: ext Pat Hayes [mailto:phayes@ai.uwf.edu]
> Sent: 04 October, 2001 17:38
> To: Stickler Patrick (NRC/Tampere)
> Cc: www-rdf-logic@w3.org
> Subject: RE: Literals (Re: model theory for RDF/S)
> 
> 
> >  > ... but you can't apply that to
> >>  literals because they can't be the subject of statements
> >>  (unless that rule
> >>  gets changed).
> >
> >This was one of my motivations for exploring the idea of tossing
> >out literals altogether, per se, and instead adopting a means
> >by which literals would be "first class" resources.
> >
> >Now, granted, a typed data value such as "5" is pretty semantically
> >"anemic", and there's probably not very many useful statements that
> >one could make about such 'resources',
> 
> I'd like to take issue with this often-repeated claim. There are all 
> kinds of useful things you could say about such things, most notably 
> asserting that they were in some named classes (such as 'odd-integer' 
> or 'goal-scores-of-Tottenham-Hotspur' ). 

But that would really have to be defined as a more general rule than
just statments about specific instances of integers, otherwise, we'd
have to define an infinite number of statements to be sure they all
were known to any system trying to ask, is this resource "odd", etc.

I.e., rather than define explicit facts, we would define functions
from which we could infer the facts implicitly only as needed.

> ... If RDF had the ability to 
> assert properties of literals, the expressive power of the language 
> would be quite radically increased.

Well, I guess I'm not sure that that is the case with literals
given a URI representation -- as then the literals are no longer
literals but resources, so how does that actually increase the
expressive power of RDF, per se -- since the semantics of the
data typing is in the URI and RDF doesn't understand the semantics
of URI schemes...?

> >(but for treating two URIs that denote the same "thing" as 
> equivalent,
> >no, RDF is IMO not the right layer, though probably RDFS is)
> 
> For the record, I tend to be careless about the distinction between 
> RDF and RDFS, which isn't particularly well-motivated or worth 
> fussing about, IMHO.

Eh?  Does that mean that the MT for RDF is really the combined
MT for RDF and RDFS? (that might explain the confusion about the
definition of "resource"...).

And isn't it useful to keep very clear and distinct the "raw"
graph versus (possibly many) "cooked" interpretive layers above
that graph?

Patrick

--
Patrick Stickler                      Phone:  +358 3 356 0209
Senior Research Scientist             Mobile: +358 50 483 9453
Nokia Research Center                 Fax:    +358 7180 35409
Visiokatu 1, 33720 Tampere, Finland   Email:  patrick.stickler@nokia.com

Received on Thursday, 4 October 2001 11:34:19 UTC