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Re: There can be only one

From: Jonathan Borden <jonathan@openhealth.org>
Date: Sat, 25 Jan 2003 10:24:58 -0500
Message-ID: <000c01c2c485$ec475ef0$7c01a8c0@ne.mediaone.net>
To: Bill de hÓra <dehora@eircom.net>
Cc: <www-tag@w3.org>

please refer to
http://lists.w3.org/Archives/Public/www-tag/2003Jan/0362.html

I misttyped 1:1 where I had intended many (URI):1 resource

A concrete example:

#foo rdf:type #Car
#foo :color :Red
#bar owl:sameIndividualAs #foo

=>

#bar rdf:type #Car .
#bar :color :Red .

my issue is the idea that 1 URI might identify _many_ resources. Perhaps its
an issue of terminology but I would say that if the _thing_ that a URI
identifies changes over time, then it is a time varying thing. It's sort of
like you and your name. You might change your clothes, hairstyle, face,
body, job, home etc. but we still of *you* as *you*. Now of course if we are
identifying *you* as dehora@eircom.net and you change your email address to
bill@dehora.org then you'd need to assert

dehora@eircom.net owl:sameIndividualAs bill@dehora.org .

and our OWL reasoners would merrily hum away making the intended inferences.
I am not suggesting that people need be (or need not be) identified by email
addresses rather using this as a quick example.

A more sophisticated model would be

#email rdf:type owl:FunctionalProperty
#BillDHora rdf:type :Person .
#BillDHora :email dehora@eircom.net .

and from this -functional property- one can lookup the resource it is
attached to. Similarly we can have owl:InverseFunctionalProperty's and so
one can create arbitrarily complex many:many relationships using
*properties* i.e. triples of <URIref,URIref,URIref>. So clearly URIref <->
URIref is many:many but for the purposes of terminology and the formalism we
have created the relationship between URIref (label) to resource (node) is
many:1.

Jonathan

>
> Jonathan Borden wrote:
>
> > And how is the URI spec to be implemented? This is the crux of the
problem.
> > If the URI spec had a formal semantics then we wouldn't have so much
leeway
> > in arguing about how it is intended to be interpreted. Indeed there are
a
> > number of folks who intend the relationship of a URI to resource be many
to
> > many! Now I say 1:1 and if the spec doesn't at the very least constrain
this
> > relationship then people seem to be free to interpret it in any way they
> > please. Perhaps that is why these arguments appear never ending.
>
> I'll chip in once, having brought up many to many recently and leave
> it at that.
Received on Saturday, 25 January 2003 10:47:09 GMT

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