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Re: Question about datatype maps

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Fri, 12 Sep 2008 11:45:37 -0400
Message-ID: <29af5e2d0809120845l352532c0t34efd2f31a57fb2d@mail.gmail.com>
To: "Boris Motik" <boris.motik@comlab.ox.ac.uk>
Cc: "Michael Schneider" <schneid@fzi.de>, "W3C OWL Working Group" <public-owl-wg@w3.org>

On Fri, Sep 12, 2008 at 11:30 AM, Boris Motik
<boris.motik@comlab.ox.ac.uk> wrote:
> Hello,
>
> The concept of a datatype map is there just to act as a container for all datatypes. Please note that this notion has been taken
> from OWL 1. Hence, instead of explaining why we removed it in OWL 2, we might as well use it. Furthermore, I find this notion quite
> useful and don't see how eliminating it would make the documents easier to understand: instead of saying "the set of supported
> datatypes", we say "a datatype map". That seems shorter, and it is also quite useful for the Semantics document(s).

Saying *the* datatype map corresponds to "the set of supported
datatypes". Saying *a* datatype map suggests that a conformant OWL
implementation might have a different one.

-Alan

>
> Regards,
>
>         Boris
>
>> -----Original Message-----
>> From: public-owl-wg-request@w3.org [mailto:public-owl-wg-request@w3.org] On Behalf Of Alan Ruttenberg
>> Sent: 12 September 2008 16:13
>> To: Michael Schneider
>> Cc: W3C OWL Working Group
>> Subject: Re: Question about datatype maps
>>
>>
>> On Fri, Sep 12, 2008 at 7:02 AM, Michael Schneider <schneid@fzi.de> wrote:
>> > Hi Alan!
>> >
>> > Alan Ruttenberg wrote:
>> >
>> >>The OWL specification has a datatype map as a parameter. It's unclear
>> >>to me what are allowable extensions in the realm of datatypes, and
>> >>whether such extensions would be desirable from an interoperability
>> >>point of view. Now that we have a wide range of datatypes, do we need
>> >>to support extensibility here? Our experience OWL 1, OWL 2, that
>> >>choice and semantics of datatypes are not a slam-dunk obvious choice,
>> >>raising questions about whether sanctioned extensions to OWL in this
>> >>dimension would be beneficial or cause more trouble than they are
>> >>worth. Of course nothing would prevent unsanctioned extensions - my
>> >>question here is of what we should encourage.
>> >>
>> >>-Alan
>> >
>> > I simply would not say anything. Of course, we cannot forbid that
>> > implementers support additional datatypes. And custom datatypes, such as
>> > complex numbers, will make sense and add value in certain domains. Interop
>> > is then given by the OWL 2 spec: As long as an ontology only uses those
>> > datatypes, which are defined in the OWL 2 spec, no problems will arise with
>> > reasoners that /at least/ support all these OWL 2 datatypes [1]. If,
>> > however, an ontology uses additional datatypes, all bets are off; but why
>> > should we care as a WG? That's then in the responsibility of those who
>> > create and use such ontologies (they have to settle on a certain reasoner,
>> > etc.).
>>
>> Well, this is kind of my point. We are currently saying *something*.
>> Why mention the concept of datatype map at all, instead of just
>> documenting the datatypes? Currently datatype maps are mentioned in
>> virtually all the documents. Wouldn't removing discussion of it and
>> instead only talking about datatypes make those documents shorter (at
>> least marginally) and easier to understand?
>>
>> -Alan
>>
>>
>> >
>> > Btw, the RDF Semantics document introduced datatype maps years ago, stating
>> > in [2]:
>> >
>> >    "RDF provides for the use of externally defined datatypes
>> >    identified by a particular URI reference.
>> >    In the interests of generality, RDF imposes minimal
>> >    conditions on a datatype. It also includes a single
>> >    built-in datatype rdf:XMLLiteral."
>> >
>> > So supporting external datatypes beyond those shipped with the standard was
>> > clearly intended.
>> >
>> > Cheers,
>> > Michael
>> >
>> > [1]
>> > <http://www.w3.org/2007/OWL/wiki/Semantics#Independence_of_the_Semantics_fro
>> > m_the_Datatype_Map>
>> > [2] <http://www.w3.org/TR/rdf-mt/#dtype_interp>
>> >
>> >
>
>
>
Received on Friday, 12 September 2008 15:46:18 UTC

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