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RE: Survey on titles for OWL2 Semantics documents

From: Michael Schneider <schneid@fzi.de>
Date: Mon, 22 Sep 2008 16:09:36 +0200
Message-ID: <0EF30CAA69519C4CB91D01481AEA06A0B99115@judith.fzi.de>
To: "Uli Sattler" <sattler@cs.man.ac.uk>, "Sandro Hawke" <sandro@w3.org>
Cc: "Ivan Herman" <ivan@w3.org>, "Bijan Parsia" <bparsia@cs.man.ac.uk>, <public-owl-wg@w3.org>
>-----Original Message-----
>From: public-owl-wg-request@w3.org [mailto:public-owl-wg-request@w3.org]
>On Behalf Of Uli Sattler
>Sent: Monday, September 22, 2008 3:11 PM
>To: Sandro Hawke
>Cc: Ivan Herman; Bijan Parsia; public-owl-wg@w3.org
>Subject: Re: Survey on titles for OWL2 Semantics documents
>
>
>
>On 22 Sep 2008, at 12:58, Sandro Hawke wrote:
>
>>
>>> On 19 Sep 2008, at 16:29, Ivan Herman wrote:
>>>
>>>> Ah! So the remark could be translated as 'there is nothing DL
>>>> specific
>>>> in it'. Right? This makes sense...
>>>>
>>>
>>> indeed, this is what I tried to say, cheers, Uli
>>
>> I'm baffled by this.
>>
>> I'm pretty sure they are not the semantics of full first-order logic.
>>
>
>no, but the basic idea and structure is the same.
>
>> And they are the semantics of OWL DL, which I understand is a
>> description logic (DL) language.  (As the W3C Recommendation on the
>> subject says, "OWL DL is so named due to its correspondence with
>> description logics".)
>>
>> So that makes them very DL specific.
>>
>> What have I got wrong about this?
>>
>
>DLs are (well-behaved) fragments of first order predicate logic, and
>they have "the same" semantics. So, if I knew something about FOL,
>then i should be able to understand the semantics -- even if i had
>never heard about DLs since there is nothing "DL specific" in them.

This may well be the case. But if I knew something about FOL, and take the
current OWL 2 Semantics, then I will definitely miss support for certain FOL
stuff. And the reason is that this semantics is restricted to the FOL
fragment sROIQ (not talking about datatypes for the moment), which is a
particular description logic. 

OWL 2 DL might well be based on a different description logic, and then
there would be a semantics which would only provide support for the language
features of that other description logic. That other semantics would
certainly be equivalent to the current semantics on those language features
common to both description logics, but the two semantics would differ on the
rest. Actually, the semantics for the one language would simply not be
applicable to ontologies containing language constructs specific to the
other language.
 
So the semantics given in the "OWL 2 Semantics" document is, in this sense,
very dependent on some particular description logic. And this suggests, in
my opinion, to give the semantics document a name that at least gives a hint
to readers that there is some description logic around, which is the base.

Cheers,
Michael


Received on Monday, 22 September 2008 14:10:19 UTC

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