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Re: prov-wg: Telecon Agenda March 8, 2012

From: Graham Klyne <graham.klyne@zoo.ox.ac.uk>
Date: Thu, 08 Mar 2012 17:22:24 +0000
Message-ID: <4F58EAD0.2050205@zoo.ox.ac.uk>
To: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
CC: public-prov-wg@w3.org
On 08/03/2012 15:44, Luc Moreau wrote:
>>> The first two look reasonable to me, but I still don't see why
>>> wasDerivedFrom(e2,e1,a,g2,u1) is needed.  Once we have expressions
>>> that explicitly name activities, how much real value is there in
>>> having the "short cut" form?  Can't this be expressed by having an
>>> explicit activity record, etc.?
>>>
>>> (I'm not suggesting the model should not be capable of expressing
>>> this information, just arguing against this overloading of the
>>> wasDerivedFrom record which AIUI is primarily an entity-entity
>>> relation.)
>>
>> It does seem like bundling everything into one
>> wasDerivedFrom(ie,e2,e1,a,g2,u1,attrs) is more complicated than simply
>> requiring three distinct statements
>>
>>  wasDerivedFrom(id1,e2,e1,dattrs)
>>  wasGeneratedBy(id2,e2,a,t2,gattrs)
>>  used(id3,a,e1,t1,uattrs)
>
> The problem is that you could have another usage
>
> used(id4,a,e1,t1',u4attrs)
>
> at a different time t1' not causing the derivation.
>
> Also, a2 could also use e2 and generate e1 at the same time as a.
>
> wasGeneratedBy(id2,e2,a2,t2,gattrs)
>   used(id3,a2,e1,t1,uattrs)
>
> So, it's essential to list the activity/usage/generation *in* the derivation
> expression.

OK, *now* I understand the driving requirement.

It's the particular derivation path that cannot (necessarily) be inferred from 
the separate statements, right?

I'll mull it over.

#g
--
Received on Thursday, 8 March 2012 17:29:25 GMT

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