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Re: semantics of daml:UnambiguousProperty

From: Jonathan Borden <jborden@mediaone.net>
Date: Tue, 23 Jan 2001 19:35:15 -0500
Message-ID: <01d701c0859d$859ca850$0a2e249b@nemc.org>
To: "Dan Brickley" <danbri@w3.org>, <www-rdf-logic@w3.org>
Dan Brickley wrote:
> A little question re DAML+OIL semantics. If a property is an unambigous
> property, does the equality specified by DAML+OIL below hold only at a
> particular point in time or does it hold across time and change?
> Eg. if I say some resource X has a foo:contact property
> whose value is some other resource Y, where Y is "the resource  whose
> personalMailbox is mailto:lighthouse-keeper@stonyisland.example.com", what
> does this mean? Might Y differ over time, so long as at any one time there
> was only a single resource with that property/value pair. What inferences
> does daml:UnambiguousProperty license in this respect?
Doesn't this depend entirely on the model? Either this mailBox is or isn't
unambiguously associated with a single person err resource. If arcs are
present between two URIs representing two people and this URI then this URI
is not a good value for this resource. Alternatively when such a value is
defined, perhaps it should flag an error to enter a second arc.

This sort of problem comes up in the real world all the time. For example in
the U.S. a social security number ought be an unambiguous identifier for a
person, except that they are reused ... it turns out that creating a truly
time invariant unambiguous property is often a  difficult and expensive
proposition but does prove good fodder for heated arguments.

Jonathan Borden
Received on Tuesday, 23 January 2001 19:48:50 UTC

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