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

From: Birte Glimm <birte.glimm@comlab.ox.ac.uk>
Date: Sun, 1 Nov 2009 16:20:14 +0000
Message-ID: <492f2b0b0911010820u542d0f2cs9fc802393dfe8ad0@mail.gmail.com>
To: Ivan Herman <ivan@w3.org>
Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
[snip]
>> 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?

No, you are right. Entailments would be different for things like
annotations I guess because under Direct Semantics these are ignored
(have no semantics) whereas under RDF Based Semantics annotations
still count. There were a view discussions around that and I am not
sure I remember that rightly, but that's how I think it is.

> 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...).

Agreed.

Birte

> 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
>



-- 
Dr. Birte Glimm, Room 306
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Received on Sunday, 1 November 2009 16:20:50 GMT

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