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

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

+1 for having a transitive form of isDerivedFrom.  Without that, it is
not possible to query for "everything that this is derived from" or
"everything that is derived from this".  Perhaps we could have an
optional stronger form meaning "all of B is derived from A", which would
surely be transitive.

Stephen Cresswell

-----Original Message-----
From: public-prov-wg-request@w3.org
[mailto:public-prov-wg-request@w3.org] On Behalf Of Luc Moreau
Sent: 29 July 2011 10:56
To: public-prov-wg@w3.org
Subject: Re: PROV-ISSUE-56
(derivation-definition-does-not-imply-transitivity): Derivation as
defined is not transitive [Conceptual Model]

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



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Received on Tuesday, 2 August 2011 17:10:16 UTC