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

I observe that this partly answers my earlier response to this question... but I 
foresee dragons here.

#g
--

Cresswell, Stephen wrote:
> 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.
>>
>>
>>
>>
>>    
>

Received on Thursday, 4 August 2011 08:42:05 UTC