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

one of the main operations on provenance graphs, and one that has been studied by groups who are interested in efficient provenance 
retrieval, is the transitive closure on the derivation relation.
It would be strange indeed to see that the standard language for provenance avoids the issue altogether.

-Paolo


On 7/29/11 10:56 AM, Luc Moreau wrote:
> 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.
>>
>>
>>
>>
>>


-- 
-----------  ~oo~  --------------
Paolo Missier - Paolo.Missier@newcastle.ac.uk, pmissier@acm.org
School of Computing Science, Newcastle University,  UK
http://www.cs.ncl.ac.uk/people/Paolo.Missier

Received on Tuesday, 2 August 2011 21:46:49 UTC