RE: [UNITS, OEP] FAQ : Constraints on data values range

>Hi all,
>
>I am the one who originally asked about this problem.
>
>Natasha : That said, I don't have an alternative solution, or any solution to
>this problem. We'll certainly have to document it somehow in the BP
>documents (the question will come up again and again), but it almost
>seems like the documentation would be "there is no good way to do
>it". Am I missing something?
>
>I've looked more deeply into the question and I realized that it is a well
>known problem. I think there is no good solution at this moment to deal with
>constraints on values. Logic deals with entities, and everything is just
>entity.
>I believe you can only reason on the nature of entities (unary predicates) and
>on the link between entities (binary predicates). The formal model is not made
>to reason on entities themselves, because in general entities are just simple
>set without any order or whatever.
>But this is not the case for datatypes. So It is legitimate that we want to
>reason on datatypes, in this case some modifications have to be made to the
>formal model.

This is not quite correct. Logic itself does not have any 
prohibitions or limitations on talking about individual values such 
as numbers, and neither does RDFS or OWL-Full.  Datatypes are just 
names (or, arguably, terms involving datatype functions) in a purely 
logical model. The prohibition on restrictions which mention datatype 
values is entirely an artifact of OWL-DL, imposed by fiat by its 
designers. (For good computational reasons, but not for logical or 
semantic reasons.)

Pat Hayes

>I recommend a paper "Web Ontology Reasoning with Datatype Groups"
>form J. Pan and I. Horrocks.
>I think this is a problem that has to be explain in a FAQ.
>
>Ben


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Received on Thursday, 15 April 2004 17:45:39 UTC