Re: Regarding the definition of IVP OF

Hi Stephen,
Very good example raised as PROV-ISSUE-29.

I think we can also generalize it to
- A IVP of B
- B IVP of C
- C IVP of A

Regards,
Luc

On 07/08/2011 04:18 PM, Cresswell, Stephen wrote:
>
> I have another issue with the current definition of "IPV of".
>
> As it currently stands, I believe that it does not exclude the 
> possibility that two bobs may be mutually "IVP of" each other -
> i.e. you could have bobs A, B such that (B IVPof A) & (A IVPof B), and 
> this is surely not intended.
>
> This could arise if, for bobs A, B :
> - A and B both represent the same entity
> - A and B share some immutable properties, and they have corresponding 
> values.
> - B has some immutable properties which correspond to mutable 
> properties of A
> - A has some immutable properties which correspond to mutable 
> properties of B
>
> Possibly the asserter-defined test (included in "IPV of" definition) 
> that real world states modelled by A and B are "consistent" may disallow
> "IPV of" in this situation.  However, unless that is guaranteed, I 
> think that the definition of "B IPV of A" (if it is still to have a 
> definition) should additionally require that:
> "A has no immutable properties which correspond to mutable properties 
> of B"
>
> Stephen
>
> -----Original Message-----
> From: public-prov-wg-request@w3.org on behalf of Khalid Belhajjame
> Sent: Fri 08/07/2011 16:01
> To: public-prov-wg@w3.org
> Subject: Regarding the definition of IVP OF
>
>
> During the F2F meeting, there was a discussion in the second day
> regarding "IVP of". The definition that was suggested during the F2F can
> be found in [1]. In my opinion, the definition of "IVP of" should be
> simplified. Specifically, I would prefer a definition that states that
> "IVP of" is an asserted relationship between two entity states. I list
> in what follows the reasons:
>
> (i) In the definition of "IVP of" [1], the conditions on the properties
> of the two entity states A and B (i.e., that the properties the entity
> states share must have corresponding values, and that some mutable
> properties of A correspond to some immutable properties of B), are not
> enough in order to infer that B is an IVP of A. This is because there is
> a third condition that is not included, because it is hard to formally
> specify, viz. A and B are consistent.
>
> (ii) A consequence of (i), is that we will not be able to automatically
> infer that an entity state B is an IVP of another entity state B. All we
> can safely do, is identify cases in which an entity state B cannot be an
> IVP of another entity state of A.
>
> (iii) Even if we find a means for formally specifying that two entity
> states A and B are consistent, e.g., using assertions, it will be
> difficult to use the definition of IVP of to make inference. This is
> because the definition of IVP of requires correspondences between the
> properties of two entity states to be specified. These correspondences
> can be complex many-to-many mappings that may turn out to be hard to
> encode using existing semantic web technologies.
>
> Thanks, khalid
>
>
>
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-- 
Professor Luc Moreau
Electronics and Computer Science   tel:   +44 23 8059 4487
University of Southampton          fax:   +44 23 8059 2865
Southampton SO17 1BJ               email: l.moreau@ecs.soton.ac.uk
United Kingdom                     http://www.ecs.soton.ac.uk/~lavm