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RE: Datatype (Map) Conformance Strangeness

From: Michael Schneider <schneid@fzi.de>
Date: Tue, 14 Apr 2009 11:59:52 +0200
Message-ID: <0EF30CAA69519C4CB91D01481AEA06A00125F811@judith.fzi.de>
To: "Ian Horrocks" <ian.horrocks@comlab.ox.ac.uk>
Cc: <public-owl-wg@w3.org>
Hi Ian!

In my opinion, your changes are a very good compromise, and perfectly
sufficient for LC publication.

Cheers,
Michael

>-----Original Message-----
>From: Ian Horrocks [mailto:ian.horrocks@comlab.ox.ac.uk]
>Sent: Tuesday, April 14, 2009 10:59 AM
>To: Michael Schneider
>Cc: public-owl-wg@w3.org
>Subject: Re: Datatype (Map) Conformance Strangeness
>
>I have some sympathy with what you say, but I still maintain that
>this is a presentational issue that can be tackled after LC, and that
>we should  minimise changes at this stage. What I did, therefore, was
>to change the name of the section to "Datatype Conformance" (good
>suggestion), and change the text slightly to emphasise that a
>datatype map is just a container for a set of datatypes. This also
>allowed me to avoid mentioning the specifics of the Direct and RDF-
>Based semantics, and to use the OWL 2 datatype map as shorthand for
>the set of datatypes specified in Section 4 of SS&FS.
>
>Datatype map is slightly overloaded in our spec in that it is used to
>mean both a definition of the set of datatypes supported and a
>semantic structure that defines the meaning of a set of datatypes (a
>6-tuple that mixes together the semantics of all the datatypes). We
>might think about changing this in the future. For now, I believe
>that it is sufficient to make it clear what is meant by datatype map
>in a given context. In Conformance it now says "In OWL 2, semantic
>conditions are defined with respect to a set of datatypes specified
>in a datatype map".
>
>Thanks for the careful reading and useful suggestions.
>
>Ian
>
>
>
>
>
>On 13 Apr 2009, at 22:09, Michael Schneider wrote:
>
>> Hi!
>>
>> I still believe that we should avoid talking about "datatype maps"
>> in the
>> Conformance document, but should talk about "sets of datatypes",
>> instead. I
>> think that it doesn't provide any relevant information to readers
>> of this
>> document to talk about datatype maps, and it distracts from the really
>> relevant bits. Talking about a datatype map instead of a set of
>> datatypes is
>> a bit like talking about the bottle, if one really wants to talk
>> about the
>> wine inside. A datatype map is more or less just a container for a
>> set of
>> datatypes, and the included datatypes are what really counts when
>> we talk
>> about conformance.
>>
>> In particular, I consider it to be more confusing than helpful to
>> say in
>> Conformance that there are two notions of a datatype map in our
>> spec. This
>> may sound to people as if the set of datatypes supported by the RDF-
>> Based
>> Semantics is different from the set of datatypes supported by "OWL 2".
>> Neither is this the case nor should it be the case (modulo
>> rdf:XMLLiteral,
>> perhaps).
>>
>> What is actually different are the two definitions of a datatype /
>> map/. But
>> my understanding is that a datatype map is mainly an "adapter" to
>> "connect"
>> a /set/ of datatypes (for example the OWL 2 datatypes) to an
>> interpretation
>> of either the RDF-Based Semantics or the Direct Semantics. And
>> since the
>> definitions of an interpretation are different for the two
>> semantics, it
>> shouldn't be too surprising that the definitions of a datatype /
>> map/ are (at
>> least slightly) different, either.
>>
>> Nevertheless, there are a still few points, which probably should be
>> changed:
>>
>> * What has been called "OWL 2 Full Datatype Map" is now called "OWL 2
>> RDF-Based Datatype Map"
>>   <http://www.w3.org/2007/OWL/wiki/RDF-Based_Semantics#def-
>> owldatatypemap>
>>
>> * Maybe we should at least rename the title of the section to
>> "Datatype
>> Conformance" instead of "Datatype Map Conformance".
>>
>> * It is not really true that the "OWL 2 Datatype Map" is defined in
>> Section
>> 4 of the Structural Spec. This section primarily only specifies
>> the /set/ of
>> datatypes of OWL 2 and its properties. There is only a slight hint
>> concerning datatype /maps/ in the beginning of this section (and I
>> wouldn't
>> be unhappy to see it completely removed). The actual definition of the
>> datatype /map/ is in Section 2.1 of the Direct Semantics:
>> <http://www.w3.org/2007/OWL/wiki/Semantics#Vocabulary>.
>>
>> Michael
>>
>>> -----Original Message-----
>>> From: Ian Horrocks [mailto:ian.horrocks@comlab.ox.ac.uk]
>>> Sent: Monday, April 13, 2009 4:50 PM
>>> To: Michael Schneider
>>> Cc: public-owl-wg@w3.org
>>> Subject: Re: Datatype (Map) Conformance Strangeness
>>>
>>> I agree with Peter that this is a technical document and not one that
>>> I would expect any "user" to be interested in -- it is mainly
>>> targeted at implementers of OWL tools who should, I assume, be
>>> familiar with terms such as datatype map. So, I don't see mentioning
>>> datatype maps here to be inherently problematical.
>>>
>>> Currently, conformance is the *only* place that specifies what the
>>> datatype map has to be when the direct semantics is applied. We can
>>> argue about the wisdom of this, but I suggest not to try to change it
>>> before LC as there is too much danger that we will just mess things
>>> up -- we could always re-organise things later as the change would
>>> only be editorial. This being the case, we can't eliminate mention of
>>> datatype maps from Conformance. I left this statement mentioning both
>>> the OWL Datatype map and the OWL 2 Full Datatype Map as it would look
>>> strangely asymmetrical otherwise, and I don't believe that this
>>> statement is actually wrong (even if it is redundant).
>>>
>>> However, it is certainly the case that the note about the datatypes
>>> that can occur in conformant OWL DL documents is in the wrong place
>>> and should *not* refer to datatype maps but rather to the set of
>>> datatypes listed in Section 4 of SS&FS (plus rdfs:Literal). I have
>>> therefore moved this note into the Document Conformance section.
>>>
>>> It is also the case that having Datatype Conformance be a subsection
>>> of Document conformance is wrong, as the former talks about semantic
>>> conditions and the latter about syntactic ones. I therefore promoted
>>> Datatype conformance into its own subsection.
>>>
>>> I think that the  above mentioned changes are sufficient for the time
>>> being -- as I said above, we can think some more about the
>>> organisation of these various documents after LC.
>>>
>>> Ian
>>>
>>>
>>> On 12 Apr 2009, at 08:46, Michael Schneider wrote:
>>>
>>>> Hi Ian!
>>>>
>>>> I argued for not talking about "datatype maps" in the Conformance
>>>> document
>>>> at all. I suggest to just talk about "(sets of) datatypes". My
>>>> proposed
>>>> revision of the section in my previous mail reflects this.
>>>>
>>>> I don't see why referring to datatype maps would be necessary or
>>>> would
>>>> provide any relevant additional information. We will just open the
>>>> Conformance document up to unnecessary criticism.
>>>>
>>>> I consider datatype maps as an internal aspect of the Direct
>>>> Semantics and
>>>> the RDF-Based Semantics. So let's talk about datatype maps
>>>> exclusively in
>>>> the semantics documents. I think it would even be best to not talk
>>>> about
>>>> datatype maps in the Structural Spec, but, again, only about
>>>> (sets of)
>>>> datatypes.
>>>>
>>>> Michael
>>>>
>>>>> -----Original Message-----
>>>>> From: Ian Horrocks [mailto:ian.horrocks@comlab.ox.ac.uk]
>>>>> Sent: Saturday, April 11, 2009 12:42 AM
>>>>> To: Michael Schneider
>>>>> Cc: public-owl-wg@w3.org
>>>>> Subject: Re: Datatype (Map) Conformance Strangeness
>>>>>
>>>>> I agree with you that this has got rather confused. I think that
>>>>> the
>>>>> problem is twofold:
>>>>>
>>>>> 1) I added the (redundant) note about conformant ontology documents
>>>>> in the wrong place -- this could actually be part of the definition
>>>>> of an OWL 2 DL ontology document (it is redundant because the
>>>>> condition is already one of the conditions that an ontology must
>>>>> satisfy in order to be an OWL 2 ontology as specified in Section
>>>>> 3 of
>>>>> SS&FS).
>>>>>
>>>>> 2) Section 2.1.2 is talking about semantic conditions, yet it is in
>>>>> the "Document Conformance section.
>>>>>
>>>>> Thus, I think that the correct way to fix the problem is:
>>>>>
>>>>> 1) Move the note on datatypes to be part of the definition of an
>>>>> OWL
>>>>> 2 DL ontology document (or get rid of it altogether).
>>>>>
>>>>> 2) Promote 2.1.2 to (sub) section 2.2 (Tool Conformance will then
>>>>> become Section 2.3).
>>>>>
>>>>> I also think that the text should be changed slightly to say:
>>>>>
>>>>> "In OWL 2, semantic conditions are defined with respect to a
>>>>> datatype
>>>>> map. This MUST be either the OWL 2 datatype map (as defined in
>>>>> Section 4 of the OWL 2 Syntax specification [OWL 2 Specification]),
>>>>> an OWL 2 RDF-Based datatype map (as defined in Section 4.1 of
>>>>> the OWL
>>>>> 2 RDF-Based Semantics [OWL 2 RDF-Based Semantics]), or an extension
>>>>> of the OWL 2 datatype map to include additional datatypes.
>>>>>
>>>>> OWL 2 Profiles may support only a reduced set of datatypes. This
>>>>> is,
>>>>> however, a syntactic condition that must be met by documents in
>>>>> order
>>>>> to fall within the relevant profile, and the semantic conditions on
>>>>> the supported datatypes are unchanged, i.e., they are still defined
>>>>> by an OWL 2 RDF-Based datatype map or a (possibly extended) OWL 2
>>>>> datatype map. These datatype maps define semantic conditions on
>>>>> unsupported datatypes, but as these datatypes never occur in
>>>>> conforming documents the additional conditions are simply
>>>>> irrelevant."
>>>>>
>>>>> I assume that it is correct to say that semantic conditions may be
>>>>> defined by an OWL 2 RDF-Based datatype map -- presumably tools
>>>>> using
>>>>> the RDF-Based semantics will use such a datatype map.
>>>>>
>>>>> Ian
>>>>>
>>>>>
>>>>>
>>>>> On 10 Apr 2009, at 16:19, Michael Schneider wrote:
>>>>>
>>>>>> Hi!
>>>>>>
>>>>>> I had a closer look at the "Datatype map conformance" section
>>>>>> (§2.1.2) in the Conformance document:
>>>>>>
>>>>>>   <http://www.w3.org/2007/OWL/wiki/index.php?
>>>>>> title=Conformance&oldid=21801#Datatype_Map_Conformance>
>>>>>>
>>>>>> I am pretty confused by the current state. I don't understand why
>>>>>> the section refers to the OWL 2 Full datatype map, or to datatype
>>>>>> maps at all? The section is still about syntactic conformance, and
>>>>>> the only relevant thing here seems to be which datatypes may occur
>>>>>> in ontologies.
>>>>>>
>>>>>> I think, the paragraph confuses two things:
>>>>>>
>>>>>> 1) The set of datatypes and their properties, i.e. value spaces,
>>>>>> lexical spaces, facets. These are specified in the Structural Spec
>>>>>> (mainly by referring to XSD and other specifications) and are
>>>>>> invariant for the Direct Semantics and the RDF-Based Semantics.
>>>>>>
>>>>>> 2) The definitions of datatype maps. These definitions are part of
>>>>>> the two semantics, and they differ from each other structurally in
>>>>>> order to match the different semantic frameworks.
>>>>>>
>>>>>> I believe only 1) is relevant for Section 2.1.2, while the
>>>>>> (different) aspects of datatype maps in 2) have no relevance for
>>>>>> syntactic conformance at all.
>>>>>>
>>>>>> Maybe the confusion already stems from the title that has been
>>>>>> chosen for this section (and has been around for a while, I
>>>>>> think):
>>>>>> I'd say that it should be changed from "Datatype Map Conformance"
>>>>>> to "Datatype Conformance", because datatype /maps/ do not really
>>>>>> play a role here, only the /set/ of datatypes supported by OWL
>>>>>> 2 is
>>>>>> of relevance.
>>>>>>
>>>>>> Here is a proposal for a revision of the Section as I think it
>>>>>> would be more appropriate:
>>>>>>
>>>>>>>>>>>>>>> BEGIN PROPOSAL <<<<<<<<<<<<<<<
>>>>>>
>>>>>> ==== Datatype Conformance ====
>>>>>>
>>>>>> In OWL 2, semantic conditions are defined with respect to a set of
>>>>>> datatypes. This <em title="MUST in RFC 2119 context"
>>>>>> class="RFC2119">MUST</em> be either the set of datatypes as
>>>>>> defined
>>>>>> in [[Syntax#Datatype_Maps|Section 4]] of the OWL 2 Syntax
>>>>>> specification [<cite>[[#ref-owl-2-specification|OWL 2
>>>>>> Specification]]</cite>]), or an extension of this set to include
>>>>>> additional datatypes.
>>>>>>
>>>>>> Note that:
>>>>>> # A conformant OWL 2 DL ontology document <em title="MUST NOT in
>>>>>> RFC 2119 context" class="RFC2119">MUST NOT</em> use datatypes
>>>>>> other
>>>>>> than those specified in [[Syntax#Datatype_Maps|Section 4]] of the
>>>>>> OWL 2 Syntax specification [<cite>[[#ref-owl-2-specification|OWL 2
>>>>>> Specification]]</cite>].
>>>>>> # OWL 2 Profiles may support only a reduced set of datatypes. This
>>>>>> is, however, a syntactic condition that must be met by
>>>>>> documents in
>>>>>> order to fall within the relevant profile, and the semantic
>>>>>> conditions on the supported datatypes are unchanged. This also
>>>>>> defines conditions on unsupported datatypes, but as these
>>>>>> datatypes
>>>>>> never occur in conforming documents the additional conditions are
>>>>>> simply irrelevant.
>>>>>>
>>>>>>>>>>>>>>> END OF PROPOSAL <<<<<<<<<<<<<<<<<
>>>>>>
>>>>>> Cheers,
>>>>>> Michael
>>>>
>>>> --
>>>> Dipl.-Inform. Michael Schneider
>>>> Research Scientist, Dept. Information Process Engineering (IPE)
>>>> Tel  : +49-721-9654-726
>>>> Fax  : +49-721-9654-727
>>>> Email: michael.schneider@fzi.de
>>>> WWW  : http://www.fzi.de/michael.schneider
>>>> ====================================================================
>>>> ==
>>>> =
>>>> FZI Forschungszentrum Informatik an der Universität Karlsruhe
>>>> Haid-und-Neu-Str. 10-14, D-76131 Karlsruhe
>>>> Tel.: +49-721-9654-0, Fax: +49-721-9654-959
>>>> Stiftung des bürgerlichen Rechts, Az 14-0563.1, RP Karlsruhe
>>>> Vorstand: Prof. Dr.-Ing. Rüdiger Dillmann, Dipl. Wi.-Ing. Michael
>>>> Flor,
>>>> Prof. Dr. Dr. h.c. Wolffried Stucky, Prof. Dr. Rudi Studer
>>>> Vorsitzender des Kuratoriums: Ministerialdirigent Günther
>>>> Leßnerkraus
>>>> ====================================================================
>>>> ==
>>>> =
>>>>
>>
>> --
>> Dipl.-Inform. Michael Schneider
>> Research Scientist, Dept. Information Process Engineering (IPE)
>> Tel  : +49-721-9654-726
>> Fax  : +49-721-9654-727
>> Email: michael.schneider@fzi.de
>> WWW  : http://www.fzi.de/michael.schneider
>> ======================================================================
>> =
>> FZI Forschungszentrum Informatik an der Universität Karlsruhe
>> Haid-und-Neu-Str. 10-14, D-76131 Karlsruhe
>> Tel.: +49-721-9654-0, Fax: +49-721-9654-959
>> Stiftung des bürgerlichen Rechts, Az 14-0563.1, RP Karlsruhe
>> Vorstand: Prof. Dr.-Ing. Rüdiger Dillmann, Dipl. Wi.-Ing. Michael
>> Flor,
>> Prof. Dr. Dr. h.c. Wolffried Stucky, Prof. Dr. Rudi Studer
>> Vorsitzender des Kuratoriums: Ministerialdirigent Günther Leßnerkraus
>> ======================================================================
>> =
>>

--
Dipl.-Inform. Michael Schneider
Research Scientist, Dept. Information Process Engineering (IPE)
Tel  : +49-721-9654-726
Fax  : +49-721-9654-727
Email: michael.schneider@fzi.de
WWW  : http://www.fzi.de/michael.schneider
=======================================================================
FZI Forschungszentrum Informatik an der Universität Karlsruhe
Haid-und-Neu-Str. 10-14, D-76131 Karlsruhe
Tel.: +49-721-9654-0, Fax: +49-721-9654-959
Stiftung des bürgerlichen Rechts, Az 14-0563.1, RP Karlsruhe
Vorstand: Prof. Dr.-Ing. Rüdiger Dillmann, Dipl. Wi.-Ing. Michael Flor,
Prof. Dr. Dr. h.c. Wolffried Stucky, Prof. Dr. Rudi Studer
Vorsitzender des Kuratoriums: Ministerialdirigent Günther Leßnerkraus
=======================================================================



Received on Tuesday, 14 April 2009 10:00:36 GMT

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