# Re: PROV-ISSUE-249 (two-derivations): Why do we have 3 derivations? [prov-dm]

From: Khalid Belhajjame <Khalid.Belhajjame@cs.man.ac.uk>
Date: Fri, 10 Feb 2012 10:13:39 +0000
Message-ID: <4F34EDD3.9030905@cs.man.ac.uk>
To: Provenance Working Group <public-prov-wg@w3.org>
CC: Provenance Working Group Issue Tracker <sysbot+tracker@w3.org>
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+1

I think this proposal will also simplify the model.
The consequence of applying this proposal will also IMO remove some
confusion, by avoiding talking about granularity of the activities
involved in the derivation. In particular, what for one observer can be
imprecise-1, because s/he believes that the activity involved in the
derivation is atomic, can be seen by another observer as imprecise-n,
because s/he believes that the activity involved in the derivation is
composite. Talking simply about precise and imprecise derivation allows
us to avoid this issue.

Khalid

On 09/02/2012 23:11, Provenance Working Group Issue Tracker wrote:
> PROV-ISSUE-249 (two-derivations): Why do we have 3 derivations? [prov-dm]
>
> http://www.w3.org/2011/prov/track/issues/249
>
> Raised by: Luc Moreau
> On product: prov-dm
>
> We currently have 3 derivations:
>
>
> A precise-1 derivation, written wasDerivedFrom(id, e2, e1, a, g2, u1, attrs)
> An imprecise-1 derivation, written wasDerivedFrom(id, e2,e1, t, attrs)
> An imprecise-n derivation, written wasDerivedFrom(id, e2, e1, t, attrs)
>
>
> Imprecise-1/imprecise-1 are distinguished with the attribute prov:steps.
>
> Why do we need 3 derivations?
>
> I believe that imprecise-n derivation is required for the 'scruffy provenance' use case.
>
> I believe that precise-1 derivation is required for the 'proper provenance' use case: in particular, it's a requirement for provenance based reproducibility.
>
> I don't understand why we have imprecise-1.  Why can we just have
> imprecise-n and precise-1?
>
> PS. If we go with this proposal, then they could simply be called imprecise/precise, and we don't need the attribute steps.
>
> PS2. They would essentially be a unqualified and a qualified derivation (in prov-o terminology).
>
>
>
>
>
>
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Received on Friday, 10 February 2012 10:14:07 GMT

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