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Re: Proposed change to the OWL-2 Direct Semantics entailment regime

From: Birte Glimm <birte.glimm@comlab.ox.ac.uk>
Date: Tue, 30 Nov 2010 15:20:12 +0000
Message-ID: <AANLkTikpOdLBLFVegALK9KEkb_Zsk+Kh-1F5frG5Yj0k@mail.gmail.com>
To: Lee Feigenbaum <lee@thefigtrees.net>
Cc: Enrico Franconi <franconi@inf.unibz.it>, SPARQL Working Group <public-rdf-dawg@w3.org>
On 30 November 2010 14:51, Lee Feigenbaum <lee@thefigtrees.net> wrote:
> On 11/30/2010 9:49 AM, Enrico Franconi wrote:
>>
>> I repeat myself: *any* OWL-QL or OWL-EL implementation by design
>> incorporates BGPs with OWL Direct Semantics in the manner I'm proposing. Not
>> having BGPs in the manner I'm proposing would force them not to adopt SPARQL
>> for their systems.

I don't know any OWL EL system that has native SPARQL support, apart
from those that do OWL DL reasoning, which is a superset of OWL EL.
>From those KAON2 and RACER only do distinguished variables, Pellet can
switch non-distinguished variables on if you want them. For HermiT we
are implementing the regime at the moment, HermiT didn't have SPARQL
support before. For Trowl I am not sure.

Apart from Quonto, which I guess from your comment has
non-distinguished variables, which imlemented systems are you
referring to?
In any system, you can always use concepts to express the existential
semantics if you want it that way. OWL DL doesn't permit any
non-tree-shaped relations among bnodes anyway because decidability is
unknown, so doing the rolling-up as a preprocessing isaways possible.
With that you can do all that you want to do in OWL QL.

Birte

> Thanks, Enrico.
>
> Birte and Bijan -- if all current SPARQL implementations that incorporate
> OWL QL or OWL EL semantics behave in this way, wouldn't we be facing a
> significant implementation cost to keep the spec "as is"? i.e. wouldn't we
> be asking all current SPARQL-OWL implementations to change their behavior?
>
> Lee (has a feeling he is not understanding something here)
>
>
>> --e.
>>
>>
>> On 30 Nov 2010, at 15:44, Lee Feigenbaum wrote:
>>
>>> On 11/30/2010 9:37 AM, Enrico Franconi wrote:
>>>>
>>>> Any OWL-QL or OWL-EL implementation by design incorporates OWL Direct
>>>> Semantics in the manner I'm proposing.
>>>> I'm too lazy to list them all.
>>>> Many of them are used in real world applications such as banking,
>>>> database integration, medical applications, etc.
>>>> cheers
>>>> --e.
>>>
>>> Hi Enrico,
>>>
>>> Thanks. I'm specifically interested in anyone doing SPARQL in the context
>>> of OWL direct semantics. Are you aware of any implementations doing this?
>>>
>>> thanks,
>>> Lee
>>>
>>>>
>>>> On 30 Nov 2010, at 15:29, Lee Feigenbaum wrote:
>>>>
>>>>> On 11/30/2010 9:20 AM, Enrico Franconi wrote:
>>>>>>
>>>>>> Be surprised: the academic, industry, and system people working on
>>>>>> OWL-QL-based systems are already very upset by the limitation of the current
>>>>>> version of the standard, and asked me to discuss the matter with the group.
>>>>>>
>>>>>>> Finally, since it's so well defined and understood its not like if it
>>>>>>> becomes suddenly known useful that there'd be any barrier to implementations
>>>>>>> picking it up.
>>>>>>
>>>>>> I fail to understand this argument. Why are we standardising
>>>>>> something, if it is already well known? Maybe to facilitate interoperability
>>>>>> of acknowledged technologies? :-)
>>>>>
>>>>> Hi Enrico,
>>>>>
>>>>> Are there existing implementations of SPARQL that incorporate OWL
>>>>> Direct Semantics in the manner you're proposing?
>>>>>
>>>>> Bijan, Birte -- do the systems that you're familiar with currently
>>>>> implement SPARQL with OWL Direct Semantics in the manner that's in the
>>>>> current entailment document, or is it not yet implemented at all?
>>>>>
>>>>> thanks,
>>>>> Lee
>>>>
>>>>
>>>>
>>
>>
>
>



-- 
Dr. Birte Glimm, Room 309
Computing Laboratory
Parks Road
Oxford
OX1 3QD
United Kingdom
+44 (0)1865 283520
Received on Tuesday, 30 November 2010 15:20:40 GMT

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