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Re: Datatype (Map) Conformance Strangeness

From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Date: Fri, 10 Apr 2009 23:41:39 +0100
Message-Id: <F9A9FDA6-D574-47FE-94FE-1AF67A92858E@comlab.ox.ac.uk>
Cc: <public-owl-wg@w3.org>
To: Michael Schneider <schneid@fzi.de>
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
> ====================================================================== 
> =
>
Received on Friday, 10 April 2009 22:42:19 GMT

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