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Re: PROV-ISSUE-467 (activity-start-req-trigger): Do activity start/end always require trigger? [prov-dm-constraints]

From: Luc Moreau <l.moreau@ecs.soton.ac.uk>
Date: Mon, 06 Aug 2012 17:30:18 +0100
Message-ID: <EMEW3|a26414c8c11121b28eb6db970885f0d9o75HUK08l.moreau|ecs.soton.ac.uk|501FF11A.6070609@ecs.soton.ac.uk>
To: public-prov-wg@w3.org
Hi Stian,

Self terminating process would be modelled like this:

wasEndedBy(end; a,-,a,t,attrs)

where a is the ended activity/process and also the ender.

There is an implicit trigger, as you say, which you can see as
the instruction to terminate, for instance.

I think this is fine.

Luc


On 06/08/12 16:28, Provenance Working Group Issue Tracker wrote:
> PROV-ISSUE-467 (activity-start-req-trigger): Do activity start/end always require trigger? [prov-dm-constraints]
>
> http://www.w3.org/2011/prov/track/issues/467
>
> Raised by: Stian Soiland-Reyes
> On product: prov-dm-constraints
>
> Do we have WG consensus on activity start/end requiring triggers?
> Can an activity terminate itself without a trigger? Start
> instantaneously?
>
> >From Stian's review http://lists.w3.org/Archives/Public/public-prov-wg/2012Aug/0021.html :
>
>
>
>> IF activity(a,t1,t2,_attrs) THEN there exist _id1, _e1, _id2, and _e2 such that wasStartedBy(_id1;a,_e1,_a1,t1,[]) and wasEndedBy(_id2;a,_e2,_a2,t2,[]).
> So it is impossible for an activity to start or end without a trigger?
> I am not so sure about this.. this creates phantom triggers, not too
> dissimilar to our previous phantom agents, in particular for a
> self-terminating process this can become a bit odd, "I'll tell my self
> to stop now!"
>
> All activities must end? Same argument as for inference 7 applies.
>
>
>
>
>
>

-- 
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 Monday, 6 August 2012 16:30:52 UTC

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