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Re: PROV-ISSUE-105: 5.3.1 Generation (current version of the conceptual model document) [Conceptual Model]

From: Stian Soiland-Reyes <soiland-reyes@cs.manchester.ac.uk>
Date: Tue, 17 Jan 2012 10:14:43 +0000
Message-ID: <CAPRnXtnsDAXbXgawoNc6J8Ak_OXb=T3VzwuKXBS9mA2B13D4hw@mail.gmail.com>
To: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Cc: public-prov-wg@w3.org
On Mon, Jan 16, 2012 at 23:21, Luc Moreau <L.Moreau@ecs.soton.ac.uk> wrote:

>> Exactly. I am not sure why is it necessary for generation of x to precede
>> end of pe since they can share the same event or time value? For example, it
>> is fairly common to state "the car production ended with the production of
>> car c1 at 10:00am on Dec 7."
> The constraint is just stating that  generation occurs during the duration
> of the activity. I don't see how it can occur before or after the activity.

What Satya is pointing out that "a precedes b" reads like
  t(a) < t(b)
  t(a) <= t(b)

I (and obviously Satya) think there's a good case for all
time-boundaries in PROV to be inclusive, other wise you are forced to
add a tiny time delta between the last generation time and the end of
the activity. (Or in a push-model, between the first usage time and
activity start).  It would also force all durations to be non-zero,
which in some models would not make sense.

Stian Soiland-Reyes, myGrid team
School of Computer Science
The University of Manchester
Received on Tuesday, 17 January 2012 10:15:35 UTC

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