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Re: PROV-ISSUE-56 (derivation-definition-does-not-imply-transitivity): Derivation as defined is not transitive [Conceptual Model]

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Fri, 29 Jul 2011 10:56:10 +0100
Message-ID: <EMEW3|a4b384fe65ba3c4a4e6931cae2c45c78n6SAuF08L.Moreau|ecs.soton.ac.uk|4E3283BA.7000502@ecs.soton.ac.uk>
To: public-prov-wg@w3.org
Hi all,

Nice counter-example, Graham!

We have the opportunity to define relationships with the properties we 
want them to have.

Do we want (a form of ) derivation to be transitive?

In the example that Graham provides, do you feel that A has some form of 
"influence" on C?
If so, would you like it to be automatically inferable in the provenance 
model?

Regards,
Luc


On 07/29/2011 10:01 AM, Provenance Working Group Issue Tracker wrote:
> PROV-ISSUE-56 (derivation-definition-does-not-imply-transitivity): Derivation as defined is not transitive [Conceptual Model]
>
> http://www.w3.org/2011/prov/track/issues/56
>
> Raised by: Graham Klyne
> On product: Conceptual Model
>
>
> [[ Given an assertion isDerivedFrom(B,A), one can infer that the use
> of characterized entity denoted by A precedes the generation of the
> characterized entity denoted by B.  ]]
> Where does this notion of "use" come from in the absence of some
> referenced activity?
>
> Concerning transitivity of derivation:
>
> Suppose:
> A has attributes a0, a1
> B having attributes b0, b1 is derived from A, with b0 being dependent on a0
> C having attributes c0, c1, is derived from B with c1 being dependent on b1
>
> So none of the attributes of C can be said to be directly or
> indirectly dependent on attributes of A, which by the given definition
> is a requirement for derivation of C from A.  Thus, as defined,
> derivation cannot be transitive.
>
> I don't really know if derivation should or should not be transitive,
> but the above seems to me like a problem of spurious
> over-specification.  My suggestion for now would be to focus on what
> really matters and see what logical properties fall out later.
>
>
>
>
>    

-- 
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
Received on Friday, 29 July 2011 09:56:45 GMT

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