Re: A description of the changes necessary to implement named data ranges

Fine with me. I just wanted to make it clear that we _decided_ not to do
it and it is not an omission.

Ivan

Peter F. Patel-Schneider wrote:
> Probably OK, but not that useful, so no real reason to add it.
> 
> peter
> 
> 
> From: Ivan Herman <ivan@w3.org>
> Subject: Re: A description of the changes necessary to implement named data ranges
> Date: Fri, 06 Mar 2009 11:40:21 +0100
> 
>> Just to clarify: what about OWL RL? Can I name a specific
>> DataIntersection (which is allowed there)? If so, there might be effects
>> on the Profile document, too.
>>
>> Ivan
>>
>> Boris Motik wrote:
>>> Hello,
>>>
>>> Here is a description of how the named data range extension would work. In
>>> short, we'd introduce a new type of axioms called DatatypeDefinition. These
>>> would allow you to define a datatype as having some built-in value. Then, you
>>> would be able to write something like this:
>>>
>>> (1) Declaration( Datatype( a:myDT ) )
>>> (2) DatatypeDefinition( a:myDT DatatypeRestriction( xsd:integer ... ) )
>>>
>>> Note that (1) is necessary because without it, axiom (2) alone would invalidate
>>> the typing constraints (it would use a URI that is not properly typed). These
>>> axioms would be mapped into RDF into (3) and (4), respectively:
>>>
>>> (3) a:myDT rdf:type rdfs:Datatype
>>> (4) a:myDT a:equivalentClass ...
>>>
>>>
>>> We would call datatypes occurring in such axioms '''defined'''. To obtain a
>>> logic with favorable computational properties, in OWL 2 DL we'd have the
>>> following conditions:
>>>
>>> - If the axiom closure contains a datatype declaration, then the datatype MUST
>>> be in the datatype map or the axiom closure MUST contain a datatype definition
>>> for the datatype.
>>>
>>> - A datatype definition axiom MUST NOT define a datatype that is in the datatype
>>> map.
>>>
>>> - Datatype definitions MUST be acyclic.
>>>
>>> - Datatype restrictions MUST involve only datatypes from the datatype map - that
>>> is, the datatypes defined through datatype definition axioms have no facets.
>>>
>>>
>>>
>>> All these changes would be reflected in the Syntax document. The impact to all
>>> other documents would be quite small:
>>>
>>> - Changes to RDF Mapping are minimal and involve mapping the new axiom (into RDF
>>> and back); both changes are minimal.
>>>
>>> - Changes to Direct Semantics are minimal and involve defining the semantics of
>>> the new axiom.
>>>
>>> - Changes to the XML Syntax are minimal and involve adding a new axiom.
>>>
>>> - There are no changes to the RDF-Based Semantics.
>>>
>>> Regards,
>>>
>>>  Boris
>>>
>>>
>> -- 
>>
>> Ivan Herman, W3C Semantic Web Activity Lead
>> Home: http://www.w3.org/People/Ivan/
>> mobile: +31-641044153
>> PGP Key: http://www.ivan-herman.net/pgpkey.html
>> FOAF: http://www.ivan-herman.net/foaf.rdf
> 

-- 

Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
PGP Key: http://www.ivan-herman.net/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf