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Re: Datatyping Summary

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Wed, 30 Jan 2002 14:54:38 +0000
Message-Id: <5.1.0.14.0.20020130145037.04e12fa8@0-mail-1.hpl.hp.com>
To: "Jeremy Carroll" <jjc@hplb.hpl.hp.com>, <w3c-rdfcore-wg@w3.org>
Ok Jeremy,

As I understand what you are suggesting here, is that under TDL, the rule 
could be rewritten to get the desired effect, i.e. reflecting the "literal 
is a pair" directly in an extended n-triples represention:

   <mary> <haircolor> (_, "red") .

and

   ?x <haircolor> (_, "red") => ?x <rdf:type> <redhead> .

one can conclude:

   ?x <rdf:type> <redhead> .

DanC - Do you buy this one.  Rewrite the rule and you get what you want.

Brian


At 09:38 30/01/2002 +0000, Jeremy Carroll wrote:

>B3 log:implies
>
>[[[
>DanC is concerened that with TDL:
>
>    <mary> <haircolor> "red" .
>
>and a rule:
>
>    ?x <haircolor> "red" => ?x <rdf:type> <redhead> .
>
>one cannot conclude
>
>    <mary> <rdf:type> <rdfhead> .
>]]]
>
>There is of course a reification in here, with a use/mention issue! Let's
>have three contentious issues in one example.
>
>I wonder whether the TDL ==> S-P syntactic transform [1] is useful here:
>(Again only for explanatory purposes, not an implementation suggestion).
>
>If we had
>   <mary> <haircolor> _:a.
>   _:a <rdf:value> "red".
>
>and the rule
>
>   ?x <haircolor> ?y .
>   ?y <rdf:value> "red" .
>      =>
>   ?x <rdf:type> <redhead> .
>
>then I can see a reading of the rule so that it fires, without any range
>constraint.
>
>As I am saying (msg with same delivery time) about the query (B4) TDL
>clairifies that one could be talking about the lexical form, or one could be
>talking about the value, and permitting a decision about which seems like a
>good choice to expose to the layer aboce RDF.
>
>So, in answer to Brian's question.
>Is the range constraint required by TDL?
>   No. It depends on the rule semantics chosen.
>   The rule implementator is free to choose.
>   In Dan's case I think he should consistently use the lexical forms of
>lexical nodes in the interpreation of the rules. I think I am saying that in
>a form #2 reification in [2], literal nodes should be mentions, i.e. in the
>model theory map them to the lexical form and ignore the value. But then
>form #2 was dropped.
>
>
>[1]Jeremy Carroll: Re: Datatyping Summary
>http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Jan/0369.html
>
>
>[2] Jan Grant. Proposals? Re: use/mention and reification
>http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Jan/0236.html
Received on Wednesday, 30 January 2002 09:55:34 EST

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