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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 12:34:42 +0000
Message-ID: <492f2b0b1002240434v45886784o7f79dd3f848ff31d@mail.gmail.com>
To: Jos de Bruijn <debruijn@inf.unibz.it>
Cc: Axel Polleres <axel.polleres@deri.org>, 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?
>
> b) seems to be the most reasonable way to go; but make sure to include
> at least one representative (for queries with blank nodes).

What do you mean with one representative. Can you give an example? I
don't see what problems queries with blank nodes cause here. Maybe I
am overlooking something?

Birte

> Unnecessarily ignoring parts of the semantics (as in a) seems rather a
> bad idea.



>
> Cheers, Jos
>
>>
>> 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
>>>
>>
>
> --
> 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 12:35:15 GMT

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