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
> ph: 1-510-540-7596
> m: 1-510-435-8234
> skype: kcoylenet
>
>
>