RE: PROV-ISSUE-29 (mutual-iVP-of): can two bobs be mutually "IVP of" each other [Conceptual Model]

Hello,

Here are my thoughts on the various specialization questions raised.

I agree with Tom and Luc that specialisation should not be about composition. Maybe this is something to note in the DM if others might read it incorrectly?

To clarify the question, these definitions were in the DM yesterday (I see specialization's is now removed):

"An entity is a thing one wants to provide provenance for."
"An entity is a specialization of another if they both refer to some common thing..."
"An entity is alternate of another if they are both a specialization of some common entity."

The first and third seem clear and tells me that an entity is one thing. But the first two together imply that a thing refers to a thing, and I understand we'd prefer to leave entity-thing relations to the formal semantics.

This may be retreading old ground, but could we define specialization something like:

  "Entity A is a specialization of entity B if A is B as it was in a more constrained period or context."

so LucInBoston is Luc in the more constrained context of being in Boston (or, equivalently, the period when he was in Boston).

I think there might always be borderline cases where it is ambiguous whether a specialization/alternate relation exists, so we can only give the intuition. It may also depend on what a strongly defined entity is in a given application.

I think it is better to avoid cases like 'the customer on the third chair'. I would not intuitively see this as one entity but if people do have a strong coherent idea of this as an entity for their cafe-based application, then I think its likely they will also have a clear idea what it means to specialise that entity to a more constrained period/context.

I think that specialization should be explicitly transitive, because I believe the value of having the relation in PROV is: if A is a specialization of B, then the provenance of A is part of the provenance of B. This seems an inherently transitive relation.

I'm agnostic as to whether it is reflexive.

thanks,
Simon

Dr Simon Miles
Senior Lecturer, Department of Informatics
Kings College London, WC2R 2LS, UK
+44 (0)20 7848 1166

Requirements for Provenance on the Web:
http://eprints.dcs.kcl.ac.uk/1399/

________________________________
From: Tom De Nies [tom.denies@ugent.be]
Sent: 02 April 2012 09:53
To: Luc Moreau
Cc: Stian Soiland-Reyes; Paul Groth; James Cheney; public-prov-wg@w3.org
Subject: Re: PROV-ISSUE-29 (mutual-iVP-of): can two bobs be mutually "IVP of" each other [Conceptual Model]

+1

I had trouble understanding the reasoning of this example as well..
In our data model, the email would rather be a collection, and the signature an element of it, rather than a specialization of it.
A specialization of "this email" would be, for example. the "printed version on my desk", which is a specialization of "my thoughts on this email thread".

Intuitively, I am having trouble coming up with a counterexample of the transitivity of our specialization.

Regards,
Tom
---
Tom De Nies
Ghent University - IBBT
Faculty of Engineering and Architecture
Department of Electronics and Information Systems - Multimedia Lab
Gaston Crommenlaan 8 bus 201, B-9050 Ledeberg-Ghent, Belgium

t: +32 9 331 49 59
e: tom.denies@ugent.be<mailto:tom.denies@ugent.be>

URL:  http://multimedialab.elis.ugent.be



2012/4/2 Luc Moreau <L.Moreau@ecs.soton.ac.uk<mailto:L.Moreau@ecs.soton.ac.uk>>

is this example really reflecting specialisation? The signature is contained in the email message. Is it a specialisation of it?

On 2 Apr 2012, at 00:11, "Stian Soiland-Reyes" <soiland-reyes@cs.manchester.ac.uk<mailto:soiland-reyes@cs.manchester.ac.uk>> wrote:

> 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.