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Re: [TF-ENT] URIs for entailment regimes in service descriptions

From: Ivan Herman <ivan@w3.org>
Date: Sun, 01 Nov 2009 16:10:12 +0100
Message-ID: <4AEDA4D4.2030304@w3.org>
To: Birte Glimm <birte.glimm@comlab.ox.ac.uk>
CC: SPARQL Working Group <public-rdf-dawg@w3.org>


Birte Glimm wrote:
> Ivan,
> that looks good. D entailment occurs twice, but that's just a copy and
> paste error I assume.

Oops, sorry

> 
> In a sense ../entailment/OWL-Direct is the same as ../owl2-profile/DL
> and ../entailment/OWL-RDF-Based is the same as ../owl2-profile/Full.
> That is why DL and Full are not really profiles, but an OWL EL
> reasoner for example also applies the direct semantics of course. To
> be consistent with OWL though, not creating the Full and DL URIs might
> make sense.

The way I understand OWL (2) is such that the linguistic restrictions
and the applied semantics are strictly separate. In theory I could use
the DL syntactical subset and apply RDF based semantics. And, at least
that is the way I understand (and I go to an area where my mathematical
understanding becomes sketchy...) on that subset it would not matter for
most of the cases, because the entailement results would be identical.
Am I far from the truth there?

That is why I think that entailement/OWL-Direct and owl2-profile/DL are
different, at least mathematically. If we talk about entailments we
should use, well, the entailments. And, well, as I said, the profile/DL
may not be that useful to have (although setting up a URI is one thing,
SPARQL may not be forced to use it...).

Ivan

> 
> Birte
> 
> 2009/11/1 Ivan Herman <ivan@w3.org>:
>> Birte,
>>
>> I was not at the call, sorry about that.
>>
>> What I try to propose to the SW Coordination Group is the following set
>> of URI-s
>>
>> http://www.w3.org/ns/entailment/Simple
>> http://www.w3.org/ns/entailment/RDF
>> http://www.w3.org/ns/entailment/RDFS
>> http://www.w3.org/ns/entailment/D
>> http://www.w3.org/ns/entailment/OWL-Direct
>> http://www.w3.org/ns/entailment/OWL-RDF-Based
>> http://www.w3.org/ns/entailment/D
>>
>> http://www.w3.org/ns/owl2-profile/Full
>> http://www.w3.org/ns/owl2-profile/DL
>> http://www.w3.org/ns/owl2-profile/EL
>> http://www.w3.org/ns/owl2-profile/QL
>> http://www.w3.org/ns/owl2-profile/RL
>>
>> This seems to cover what the RIF group requires, it seems to be o.k. for
>>  OWL (although you might want to convince Ian that the profile ones are
>> necessary) and seems to cover what SPARQL needs.
>>
>> What may be controversial whether the Full and DL profiles are really
>> necessary; after all, DL is a syntactic subset of OWL ie, it is a
>> profile although the term is not used. But if we do not need it, we can
>> just not create those for now.
>>
>> Does this work for you, ie, for SPARQL?
>>
>> Thanks!
>>
>> Ivan
>>
>>
>>
>>
>> Birte Glimm wrote:
>>> Hi all,
>>> in the telecon we shortly discussed whether we would need two URIs for
>>> the two OWL Semantics (RDF-Based and Direct (<- Model Theoretic,
>>> Description Logics)) or URIs for each OWL Profile.
>>> For RDF-Based seantics, we have two profiles:
>>> OWL Full and OWL RL
>>> OWL Full handles all legal RDF graphs and so does an OWL RL system.
>>> For OWL RL, if the input belongs to a certain fragment (the OWL RL
>>> fragment), then the system is guaranteed to sound and complete,
>>> otherwise the system might be incomplete.
>>>
>>> For Direct semantics we have three profiles:
>>> OWL QL, OWL EL, and OWL DL
>>> Any OWL DL reasoner can handle all three (but not arbitrary OWL Full).
>>> OWL EL reasoners can also handle OWL QL, and OWL QL reasoners do only
>>> OWL QL.
>>> Inputs outside of the supported fragment will be rejected, i.e., an
>>> OWL QL system works only on inpus that fall into the OWL QL fragment.
>>> OWL EL systems will accept inputs that fall into the EL (and thus also
>>> into the QL) fragment, etc
>>>
>>> The problem with using just one URI per semantics is that OWL QL and
>>> EL systems will possibly reject many input ontologies that are OWL DL
>>> because they are outside of their fragment. If we have just one URL,
>>> then I cannot know what the system will accept. It is trial and error.
>>> For RDF-Based semantics it seems to be less of an issue, but for
>>> Direct Semantics it would make more sense IMO to have different URIs
>>> and then it would be a bit wired to have only one for RDF-Based
>>> semantics, but three for Direct Semantics.
>>>
>>> Birte
>>>
>> --
>>
>> Ivan Herman, W3C Semantic Web Activity Lead
>> Home: http://www.w3.org/People/Ivan/
>> mobile: +31-641044153
>> PGP Key: http://www.ivan-herman.net/pgpkey.html
>> FOAF: http://www.ivan-herman.net/foaf.rdf
>>
> 
> 
> 

-- 

Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
PGP Key: http://www.ivan-herman.net/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf

Received on Sunday, 1 November 2009 15:10:42 GMT

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