RE: Question about value vocabularies and range

If I’m reading this right, it means that BCP-47 tokens could be modeled like so:

 

abox:expression a frbr:Expression;

                dcterms:language [ a lexvo:Language;

                                rdf:value “en-US”;

                                rdfs:comment “See BCP-47”;

                ] ;

                .

 

The BCP-47 components could be broken down, but in principle the rdf:value should be a reasonable stopping place.

 

Jeff

 

From: public-lld-request@w3.org [mailto:public-lld-request@w3.org] On Behalf Of Jon Phipps
Sent: Friday, May 06, 2011 11:10 AM
To: Karen Coyle
Cc: public-lld
Subject: Re: Question about value vocabularies and range

 

Hi Karen,

On Thu, May 5, 2011 at 8:34 PM, Karen Coyle <kcoyle@kcoyle.net> wrote:

I have a question that MAY be an OWL question, and it MAY be an 
Application Profile question.

Presume I have an RDF-define property meaning something like "Language 
of text." I would like to say that the values for this property must 
be taken from an EXTERNAL (but URI-identified) list, like ISO 639-n. 
owl:allValuesFrom looks like it's heading in the right direction, but 
can't exactly do this (or if it can, PLEASE explain!).

Can you explain why it can't exactly do this? Basically the owl restriction owl:allValuesFrom says that any value for "Language of text" must considered to be of a particular type (member of a specific class).

 

To use this restriction with "iso-639-n" (http://id.loc.gov/vocabulary/iso639-2 for instance), that resource would have to be declared as an owl:Class (which it's not) or it could be inferred to be an owl:Class. Lingvoc for instance defines its BCP 47 compliant language ontology (http://lexvo.org/ontology#Language) explicitly as an owl:subClass of <http://purl.org/dc/terms/LinguisticSystem>. It would be helpful if the id.loc.gov vocabularies declared themselves to be an owl:Class and also subclassed dct:LinguisticSystem in order to make the connection explicit rather than implied.

 

Owl:allValuesFrom is very similar to rdfs:range, except it's applied to a specific class of resources rather than any resource to which the property might be applied. 

 

Neither of these is a value restriction as might defined in an xml schema, but a consistency restriction that simply says that if the type/class of the value can't be determined it must be assumed to be a member of the class (consistent even if invalid), or if the value _can_ be determined to be a member of a class, then if it's explicitly _not_ a member of the iso-639-n class it's inconsistent with the class defined for allowable values.

 

I hope that makes sense. And if it does, how does that not do what you want? At least in an RDF context.

 

Jon

 

 
 This is a pattern that I think we will want to use frequently in 
 library data. When I was working on the DCMI Application Profile 
 document I ran into exactly this same problem but didn't pursue it 
 further.
 
 All ideas welcome.
 kc
 
 --
 Karen Coyle
 kcoyle@kcoyle.net http://kcoyle.net

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