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Re: finite approximation of the minimal Herbrand model for a RIF Core/BLD ruleset.

From: Birte Glimm <birte.glimm@comlab.ox.ac.uk>
Date: Wed, 24 Feb 2010 12:27:56 +0000
Message-ID: <492f2b0b1002240427w493fa636xf8173f1806ce74f9@mail.gmail.com>
To: Axel Polleres <axel.polleres@deri.org>
Cc: Jos de Bruijn <debruijn@inf.unibz.it>, Sandro Hawke <sandro@w3.org>, SPARQL Working Group <public-rdf-dawg@w3.org>
[snip]
> A common way to deal with this in a finite approximation way is
> a) ignoring (specifically the infinite) axiomatic triples alltogether
> b) take only those from the infinite axiomatic triples (those about container membership properties)
> that appear in the graph... I believe the latter is what we do in the current RDF(S) entailment regime, yes Birte?

That's what we do. Really similar to what ter Horst proposed, but ter
Horst takes the largest n such that rdf_:n occurs in the input and
then allows all non-container membership axiomatic triples plus
container membership axiomatic triples with rdf:_m and m<n and we just
allow all  non-container membership axiomatic triples plus container
membership axiomatic triples with rdf:_n such that rdf:_n occurs in
the input.

Birte

> Axel
>
>>
>>
>> Jos
>>
>> >
>> > Axel
>> >
>> >
>> >> ============================================================================
>> >> On 2010-02-24 12:07, Axel Polleres wrote:
>> >>>
>> >>> On 24 Feb 2010, at 11:04, Jos de Bruijn wrote:
>> >>>> On 2010-02-24 11:28, Axel Polleres wrote:
>> >>>>> Hi Jos,
>> >>>>>
>> >>>>> Can you check this briefly and tell me whether I don't oversimplify
>> >>>>> things here?
>> >>>>
>> >>>> I will have a more detailed look at it later on, but a few first comments:
>> >>>> - you do not consider equality between data values, e.g.
>> >>>> "1"^^int="1"^^decimal
>> >>>
>> >>> hmmm, I am at the moment, not sure how far this is a problem, but I definitly should include this in the issues!
>> >>>
>> >>>
>> >>>> - I did not see how a minimal model for RIF-RDF combinations is defined,
>> >>>> in particular I see no blank nodes or RDF(S) semantics
>> >>>
>> >>> ? Can't we just treat them as skolem constants? We are just interested in query answering...
>> >>
>> >> 1- if you treat blank nodes as skolem constants you need to say so.
>> >> 2- the RDF(S) semantics gives you more than just blank nodes.
>> >>
>> >>> if you agree, I forward your comments to SPARQL, ok?
>> >>
>> >> Sure.
>> >>
>> >>
>> >> Jos
>> >
>> >
>>
>> --
>> Jos de Bruijn
>>   Web:   http://www.debruijn.net/
>>   Phone: +39 0471 016224
>>   Fax:   +39 0471 016009
>>
>
>



-- 
Dr. Birte Glimm, Room 306
Computing Laboratory
Parks Road
Oxford
OX1 3QD
United Kingdom
+44 (0)1865 283529
Received on Wednesday, 24 February 2010 12:28:31 GMT

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