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Re: [RDF+OWL] Way of connecting RDF and RIF lists

From: Jos de Bruijn <debruijn@inf.unibz.it>
Date: Tue, 21 Apr 2009 15:55:52 +0200
Message-ID: <49EDD068.9010909@inf.unibz.it>
To: Dave Reynolds <der@hplb.hpl.hp.com>
CC: RIF <public-rif-wg@w3.org>

Dave Reynolds wrote:
> Look like good proposals.

So you do not have a problem with the slight change in the semantics of
RDF lists (in combinations) implied by the proposal?

> My assumption is that we'd want the one-to-one mapping but that's to be
> discussed I guess.

The argument against the one-to-one mapping is that it's harder to
implement.  I believe you cannot implement it in a rule system that does
not support function symbols, unless you have specific machinery for
manipulating the RDF list structures while you manipulate the RIF
structures: the construction of an RIF list implies the existence of a
bunch of objects used for the structure of the RDF list.

By the way, I believe that even the "RIF lists as extensions" is not so
straightforward to implement, especially when using the RDFS semantics.
You can do things like creating sub properties of rdf:first, and so you
cannot read the structure of the lists from the syntax of the graph.
For embedding this semantics (in the appendix of this specification) I
was thinking of restricting the use of rdf:first, rdf:rest, and rdf:nil
in combinations, so that the RIF lists can simply be constructed from
the RDF lists in the graphs.

> Minor comment:
> The phrasing of the additional semantic condition (9) uses the term
> "identifies". Most RDF lists are constructed with blank nodes for which
> "identify" seems like the wrong term.  I think is just an editorial
> rather than a substantive remark.

I changed it to "refers to".


> Dave
> Jos de Bruijn wrote:
>> At the face-to-face, there seemed to be some support for connecting RDF
>> lists and RIF lists in RDF-RIF combinations.  I believe this can be done
>> by suitably extending the semantics of this combinations.  The following
>> wiki page lists two possible extensions that both seem somehow
>> reasonable.  Note that in both extensions the semantics of RDF lists is
>> slightly restricted: we cannot allow the same element to identify two
>> different lists.  This is illustrated by the test cases on the same wiki
>> page:
>> http://www.w3.org/2005/rules/wiki/RIF-RDF-Lists
>> Best, Jos

+43 1 58801 18470        debruijn@inf.unibz.it

Jos de Bruijn,        http://www.debruijn.net/
Many would be cowards if they had courage
  - Thomas Fuller

Received on Tuesday, 21 April 2009 13:56:33 UTC

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