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

RE: heading toward datatyping telecon

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Wed, 7 Nov 2001 10:54:46 -0600
Message-Id: <p0510105ab80f15dd0316@[65.212.118.166]>
To: Patrick.Stickler@nokia.com
Cc: w3c-rdfcore-wg@w3.org
>
>The problem I have with this [P] approach is that it mixes
>the datatype classes with property classes -- maybe that's
>not such a big deal, but something in my gut doesn't like
>it.

Ah, that is precisely why I *do* like it. After all, RDFS is supposed 
to be the central, canonical, universal class reasoning engine; and 
here we have a class heirarchy of central importance to the language. 
It seems to me that if RDFS is unable to describe its own datatyping 
class heirarchies, then it really isn't doing very well as a class 
reasoner.

>I think it is because I'm expecting to get
>
>     _:anon  rdf:value "0x12" .
>     _:anon  rdf:type  <#hexInteger> .
>
>The fact that the type is "hidden" in the property seems
>less clean to me. Of course, that's just a subjective
>impression, but ...

Again, this seems like a bug/feature disagreement.

>I can see that both the P and S approaches are trying to
>reduce the number of arcs/nodes in the graph and make the
>relationship between literal and type tighter, but both
>seem equally successful and unsuccessful. P makes the type
>relation clear but "hides" the lexical form in a label
>that I can't see how I get at in the graph apart from
>extracting it from the nodeID. S makes the lexical form
>clear but hides the type semantics behind property semantics,
>which could be confusing. Both shrink the graph the same
>amount.

I think we are seriously confused here somewhere. First, neither P 
nor S  'shrink' the graph. P leaves the graph alone, X shrinks it, 
and S enlarges it. Second, both P and S have untyped literals as node 
labels, so they seem to be entirely equivalent as far as 'hiding' 
lexical forms goes (whatever that means).

>
>The X approach shrinks the graph even more, and apart
>from having to parse the URV, keeps the type and lexical
>form explicit.

Explicit in the label but not accessible to a reasoner, which is what 
worries me.

Pat
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Received on Wednesday, 7 November 2001 11:54:40 EST

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