RE: definition/assertion (WAS rdf as a base for other languages)

> > > a triple connecting a parent with a child, in a 
>subject-predicate-object format of person-parentOf-child, leaves 
>much unsaid -- a parent may
>
> > > have several children. If predicates serve as functions, then 
>this "function" might not have a well-defined value precisely 
>because the value
>
> > > could be any of a number of children. Of course one could make 
>the object a list, but that too has drawbacks. Logic long ago 
>handled >
>
> > > these matters by distinguishing between relations and 
>functions. But because relations can be multi-placed and do not 
>always fall neatly >
>
> > > into the subject-predicate-object framework, they are anathema 
>to many, to the detriment of the representational tools.
>
>
> > To be fair to RDF, I think itis based on the relational intepretation.
>
>A quick glance at the RDF spec shows you are probably right. Point 
>taken. But then I wonder how one could distinguish a relation from a 
>well-defined function in RDF ...

You can't in RDF, as far as I can tell, since it has no notion of 
equality. You can in DAML, with some awkwardness, by defining it as a 
property (= binary relation) with a uniqueness condition.

Pat Hayes

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