Re: Social meaning discussion 6th March

[...]

>>Use case: I want to add 'foaf:uncle' to my FOAF vocabulary at
>>http://xmlns.com/foaf/0.1/ and intend to express as much of the
conventional
>>meaning of 'uncle' as I can with the technology available, ie. RDFS +
>>OWL + N3 + HTML/prose. In the case of 'uncle', most of the meaning is
invisible
>>to RDF/S and OWL. But most of it could be handled by N3 rules, assuming
>>we had foaf:parent, foaf:sibling, gender vocab etc.
>>
>>
>Well, that is a big assumption.    So let's be sepcific
>
>{ ?x :uncle ?y } log:iff  {  ?x   :parent  [  :brother ?y ] }.
>
>is a precise definition of the term for someone for whom parent and
brother
>are defined.  But this of course doesn't really help us as somewhere the
>thing has to be grounded in english.
>
>'"?x :uncle ?y" indicates that y is the uncle of x'
>
>is an english definitoin which will do for a lot of people.
>I would expect a good spec to have both.
>The formal  information is a useful axiom.

I don't think it's an iff as it could be the case
that
  {?c :parent ?p. ?p :sister ?s. ?s :spouse ?u}
  =>
  {?c :uncle ?u}.

and the ?c, ?u substitutions for those cases aren't
necessarily implying
  {?c :parent ?p. ?p :brother ?u}.


-- ,
Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/

PS1 That's not to say that iff's are meaningless ;-)