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Re: plural vs singular properties (a proposal)

From: Sandro Hawke <sandro@w3.org>
Date: Mon, 23 Apr 2007 11:00:47 -0400
To: Bijan Parsia <bparsia@cs.man.ac.uk>
Cc: semantic-web@w3.org
Message-Id: <20070423150047.9BC584F119@homer.w3.org>


[ thanks for all the comments...   I want to clarify this point before
replying to some of the others. ]

> > Style 2 - Plural (Collection) Property
> >
> >     Turtle:   p:Charles f:children ( p:William p:Harry ).
> >
> >     N-Triples:
> >               p:Charles f:children _:genid2 .
> >               _:genid2 rdf:first p:William .
> >               _:genid2 rdf:rest _:genid1 .
> >               _:genid1 rdf:first p:Harry .
> >               _:genid1 rdf:rest rdf:nil .
> >
> > I believe the dominant opinion is that one should use Style 1  
> > unless one
> > needs one of the key features of Style 2, which are roughly:
> >     a.  the values are ordered
> >     b.  the values are exhaustive
> 
> Since it ensures neither, I think style 2 is a huge anti-pattern. I  
> recommend it against it always.

Can you explain this?  

In what sense are the elements in the list not ordered?

By "exhaustive", just to be clear, I mean that using Style 2 one can
define "children" such that when we list Charles' children we are also
saying these are his *only* children.  Is your point that such a
constraint on p:children can't be specified in OWL?

Alan points out that one can do that with OWL maxCardinality.  To do
that, you'd need to introduce classes like ParentWithTwoKids,
ParentWithThreeKids, etc, and then say:

     p:Charles a f:ParentWithTwoKids;
               f:child p:William, p:Harry.


right?

     -- Sandro
Received on Monday, 23 April 2007 15:00:49 GMT

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