- From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
- Date: Mon, 2 Apr 2012 05:04:23 +0000
- To: Stian Soiland-Reyes <soiland-reyes@cs.manchester.ac.uk>
- CC: Paul Groth <p.t.groth@vu.nl>, James Cheney <jcheney@inf.ed.ac.uk>, "public-prov-wg@w3.org" <public-prov-wg@w3.org>
Stian Concretely, what are the answers to the question I raised, and the impact on transitivity? Professor Luc Moreau Electronics and Computer Science University of Southampton Southampton SO17 1BJ United Kingdom On 2 Apr 2012, at 00:11, "Stian Soiland-Reyes" <soiland-reyes@cs.manchester.ac.uk> wrote: > On Sun, Apr 1, 2012 at 21:52, Paul Groth <p.t.groth@vu.nl> wrote: >> Your example is correct...but I the common thing were talking about is the >> thing in the chair, >> >> But maybe the gurus should step in > > I'm not claiming to be a guru on the matter, but we've had this > discussion ( a few times!) before. > > If we assume every entity only maps to one thing in the world - and > all those things are distinguishable, then we are enforcing a > particular classification of things. (that there is some "real thing" > in the end). How do we define a thing? What do you mean by "the car", > do you include the petrol or not? Well, one way is to describe it as > an entity. > > Two entities could be describing the ''same thing" if the two > interpretations overlap. The now famous "Customer in chair at 6pm" > entity overlaps with the "Woman in red dress" entity - they are > alternates of the "same thing", as they are both specializations of > the same woman, let's call her Julie. CustomerInChairAt6Pm is also a > specialization of CustomerInChair, and alternate of > CustomerInChairAt7Pm. > > However they don't continue to be 'the same thing' as Julie gets up at > 7pm to leave the cafe, and Bob sits down in her chair. > CustomerInChairAt6pm disappears (is *consumed* by the Leaving > activity, if you like), but Julie still wears her red dress; > JulieInRedDress lives on. The CustomerInChairAt7pm has nothing to do > with JulieInRedDress; they are not the same thing. > > > In this case it was the passing of time that caused the > same-thing-entities to transition to other entities which are not the > same thing. > > For conceptual things this can happen in other ways, for instance, > imagine the genome sequence GATTACA is a specialization of "the human > genome sequence", which is an specialization of the actual genome > sequences from a selection of humans. However as the human genome is a > kind of idealized average, some of those humans might not have GATTACA > in their genome, and so here it would not be transitive. (I know this > is pushing it a bit, as you could rather say that the idealized > sequence is derived from the actual sequences - however you often find > derivation and specialization go hand in hand). > > My signature in the end of this email is a specialization of this > email message, which is a specialization of my thoughts on this email > thread. However the signature is not a specialization of those > thoughts. > > -- > Stian Soiland-Reyes, myGrid team > School of Computer Science > The University of Manchester
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