W3C home > Mailing lists > Public > www-rdf-logic@w3.org > November 2001

Re: literals and typing

From: Sergey Melnik <melnik@db.stanford.edu>
Date: Fri, 09 Nov 2001 19:21:35 -0800
Message-ID: <3BEC9D3F.8F20D403@db.stanford.edu>
To: Geoff Chappell <geoff@sover.net>
CC: Pat Hayes <phayes@ai.uwf.edu>, www-rdf-logic@w3.org
Geoff Chappell wrote:
> 
> > -----Original Message-----
> > From: www-rdf-logic-request@w3.org
> > [mailto:www-rdf-logic-request@w3.org]On Behalf Of Pat Hayes
> > Sent: Friday, November 09, 2001 4:18 PM
> > To: Geoff Chappell
> > Cc: www-rdf-logic@w3.org
> > Subject: Re: literals and typing
> > >>
> > >>  To elaborate on the above, BTW, I just posted a longer comparison:
> > >>  http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Nov/0295.html
> > >>
> > >
> 
> [...]
> 
> >
> > Well, yes; but all the proposals have snags, unfortunately. I wish
> > there was a clear winner, but I think we will have to compromise
> > somewhere. I personally would love to see something like X, in its
> > stark simplicity, but I doubt if the RDF core WG will be willing to
> > adopt a new, unproven, URI scheme as part of the standard. And the P
> > schemes are rather 'delicate' in that they require datayping schemes
> > to be carefully crafted to be upward compatible, and will completely
> > fail if they are not.
> 
> If I understand the delicacy issue with P/P++ it's that a class and one of
> its subclasses might have different lexical domains (e.g. hexint, int) and
> so it will be unclear/ambiguous in which form the literal value is actually
> encoded as a string. But doesn't the same issue exist with S? if we have:
> (#whoknows hexint "70") and (hexint subPropertyOf int) we can infer
> (#whoknows int "70"). Can't these problems exist in any of the schemes
> except X (and only not there because types aren't exposed to inference -
> i.e. there are no datatypes visible to RDF).

In S, asserting (hexint subPropertyOf int) yields an empty
interpretation (in other words, this assertion is inconsistent with the
definition of hexint and int). You wouldn't want to assert things like
that...

Sergey

> 
> >
> > Pat
> 
> Geoff
Received on Friday, 9 November 2001 21:54:33 UTC

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