+1


On Fri, Sep 13, 2013 at 8:51 AM, Esmé Cowles <[log in to unmask]> wrote:

> Thomas-
>
> This isn't something I've run across yet.  But one thing you could do is
> create some URIs for different kinds of unknown/nonexistent titles:
>
> example:book1 dc:title example:unknownTitle
> example:book2 dc:title example:noTitle
> etc.
>
> You could then describe example:unknownTitle with a label or comment to
> fully describe the states you wanted to capture with the different
> categories.
>
> -Esme
> --
> Esme Cowles <[log in to unmask]>
>
> "Necessity is the plea for every infringement of human freedom. It is the
>  argument of tyrants; it is the creed of slaves." -- William Pitt, 1783
>
> On 09/13/2013, at 7:32 AM, "Meehan, Thomas" <[log in to unmask]> wrote:
>
> > Hello,
> >
> > I'm not sure how sensible a question this is (it's certainly
> theoretical), but it cropped up in relation to a rare books cataloguing
> discussion. Is there a standard or accepted way to express negatives in
> RDF? This is best explained by examples, expressed in mock-turtle:
> >
> > If I want  to say this book has the title "Cats in RDA" I would do
> something like:
> >
> > example:thisbook dc:title "Cats in RDA" .
> >
> > Normally, if a predicate like dc:title is not relevant to
> example:thisbook I believe I am right in thinking that it would simply be
> missing, i.e. it is not part of a record where a set number of fields need
> to be filled in, so no need to even make the statement. However, there are
> occasions where a positively negative statement might be useful. I
> understand OWL has a way of managing the statement This book does not have
> the title "Cats in RDA" [1]:
> >
> > []  rdf:type owl:NegativePropertyAssertion ;
> >     owl:sourceIndividual   example:thisbook ;
> >     owl:assertionProperty  dc:title ;
> >     owl:targetIndividual   "Cats in RDA" .
> >
> > However, it would be more useful, and quite common at least in a
> bibliographic context, to say "This book does not have a title". Ideally
> (?!) there would be an ontology of concepts like "none", "unknown", or even
> "something, but unspecified":
> >
> > This book has no title:
> > example:thisbook dc:title hasobject:false .
> >
> > It is unknown if this book has a title (sounds undesirable but I can
> think of instances where it might be handy[2]):
> > example:thisbook dc:title hasobject:unknown .
> >
> > This book has a title but it has not been specified:
> > example:thisbook dc:title hasobject:true .
> >
> > In terms of cataloguing, the answer is perhaps to refer to the rules
> (which would normally mandate supplied titles in square brackets and so
> forth) rather than use RDF to express this kind of thing, although the
> rules differ depending on the part of description and, in the case of the
> kind of thing that prompted the question- the presence of clasps on rare
> books- there are no rules. I wonder if anyone has any more wisdom on this.
> >
> > Many thanks,
> >
> > Tom
> >
> > [1] Adapted from
> http://www.w3.org/2007/OWL/wiki/Primer#Object_Properties
> > [2] No many tbh, but e.g. title in an unknown script or indecipherable
> hand.
> >
> > ---
> >
> > Thomas Meehan
> > Head of Current Cataloguing
> > Library Services
> > University College London
> > Gower Street
> > London WC1E 6BT
> >
> > [log in to unmask]
>