RE: Datatype (Map) Conformance Strangeness

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
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