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Re: PROV-DM derivation concerns arising from my primer review

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Thu, 17 Nov 2011 11:55:05 +0000
Message-ID: <EMEW3|4c8be2fcef3a49664754a96c2f3eba48nAGBy808L.Moreau|ecs.soton.ac.uk|4EC4F619.2060002@ecs.soton.ac.uk>
To: public-prov-wg@w3.org
Hi Graham,

The derivation section is indeed complex and needs simplification.

I recently made this proposal

It differs from yours as follows.

Two derivations:
- wasDerivedFrom: activity linked
- wasEventuallyDerivedFrom (replaced by an adequate name)

Simon has made the case that wasEventuallyDerivedFrom is not transitive. 
I think
it's reasonable.

So, what's the difference? wasDerivedFrom is associated with one and 
only one activity.
  wasEventuallyDerivedFrom is unspecific about activities behind this 
    (but I believe there is some activity, we just don't know them, nor 
their number).
So, wasDerivedFrom would be a special case of wasEventuallyDerivedFrom.

Several of us have indicated it is useful to have a transitive version.  
Stian has a good
idea that the transitive version could also include control and 
wasComplementOf (a bit
like participation was defined, but transitive).

This is a much weaker relation, which states that one entity was in the 
provenance of
another, essentially. It's not a  derivation.
  I would define this in the "Common Relation" section. Not sure how we 
name this, though.

Views? Comments?


On 11/17/2011 11:31 AM, Graham Klyne wrote:
> I'm reposting and slightly expanding a couple of PROV-DM issues that 
> came up in my review of the primer under a separate subject line.  
> They are related to derivation:
> http://dvcs.w3.org/hg/prov/raw-file/tip/model/ProvenanceModel.html#Derivation-Relation 
> My understanding of what PROV-DM defines:
> (a) wasDerivedFrom - activity-linked direct derivation
> (b) eventuallyDerivedFrom - activity-independent derivation relation 
> with explicit impact on result
> (c) dependedOn - activity-independent derivation relation possibly 
> without impact on result
> == Two or three kinds of derivation? ==
> "PROV-DM offers two different forms of derivation records."
> "The three kinds of derivation records are successively introduced."
> == eventuallyDerivedFrom vs dependedOn ==
> I have never been particularly comfortable with this attempt to 
> capture the distinction between something that was merely involved and 
> something that actively informed the resulting entity.  
> Philosophically, I think it's a very tricky distinction to draw.  
> Also, it draws us into discussion of what might have been, which is 
> something I understand that provenance is not intended to capture.
> In the primer example given about "DRAFT FOR REVIEW", maybe its 
> presence does have an effect on the eventual document; if it were not 
> present, the document might have been published without further 
> revision.  Who knows?  I think there may be cases where the form of 
> contribution is clearer and testable (e.g. becamePartOf),  but to 
> simply distinguish between contributory and non-contributory 
> derivation is, I think, rather hard to do.
> My suggestion would be to drop the distinction, but to allow 
> applications to specialize the property in ways that make sense for 
> the application.
> == Direct derivation with unspecified action ==
> Is it possible to state that there is a direct derivation relation 
> between two entities by some unspecified (existentially quantified) 
> process execution?
> I think this is possible using expressions like 
> "wasDerivedFrom(e2,e1)".  It is stated, but I found it took some 
> digging out of the text.
> ...
> My preference would be to have just two derivation properties:
> (1) wasDerivedFrom - transitive, activity-independent, 
> account-independent. This would effectively be a superproperty of all 
> derivation relations.
> (2) wasDirectlyDerivedFrom - non-transitive, activity-dependent 
> (though the activity may be existentially inferred if not specified), 
> and account-dependent.
> Other application-specific subproperties of wasDerivedFrom could be 
> introduced as needed to capture more directly traceable notions of 
> (esp. multi-step) derivation.
> (I think this is closer to the original OPM model, which made more 
> sense to me).
> #g
> -- 

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 Thursday, 17 November 2011 11:55:45 UTC

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