Re: PROV-ISSUE-121: Constraint on PE (PROV-DM and PROV-OM) [Conceptual Model]

Thanks Satya, it's now closed.
Luc

On 11/01/12 21:05, Satya Sahoo wrote:
> Hi Luc,
> I agree that the points in this issue have either been superseded by 
> updates or raised as new issues - we can close this issue.
>
> Thanks.
>
> Best,
> Satya
>
> On Tue, Dec 20, 2011 at 11:38 AM, Luc Moreau <L.Moreau@ecs.soton.ac.uk 
> <mailto:L.Moreau@ecs.soton.ac.uk>> wrote:
>
>     Hi Satya,
>
>     The ordering constraints are all now in a single section
>     http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#interpretation
>
>     ISSUE-82 was closed after a month without any objection to its
>     proposed resolution.
>
>     I am proposing to close this issue, pending review.
>
>     Best regards,
>     Luc
>
>
>
>
>     On 10/09/2011 10:54 PM, Provenance Working Group Issue Tracker wrote:
>
>         PROV-ISSUE-121: Constraint on PE (PROV-DM and PROV-OM)
>         [Conceptual Model]
>
>         http://www.w3.org/2011/prov/track/issues/121
>
>         Raised by: Satya Sahoo
>         On product: Conceptual Model
>
>         PE Constraint defined in the PROV-DM document (as on Oct 9, 2011):
>         "The mere existence of a process execution assertion entails
>         some event ordering in the world, since the start event
>         precedes the end event. This is expressed by constraint
>         start-precedes-end.
>         > From a process execution expression, one can infer that the
>         start event precedes the end event of the represented activity."
>
>         There are multiple issues with the above constraint:
>
>         1. The constraint is defined with respect to events (in
>         previous version of PROV-DM it was defined with respect to
>         time), and event (a) is not defined, and (b) is not part of
>         either the definition of PE or the PE expression. Hence, it is
>         not clear how can this constraint can be defined and enforced
>         for PE?
>
>         In other words, the "mere existence of a process execution"
>         cannot entail "some event ordering in the world" since a PE
>         can be defined without making any assertion about events
>         (start or end).
>
>         2. Issue 82 discussed the introduction of event as concept but
>         there was no final decision, hence pending clarification about
>         its status in PROV (both DM and OM), we should not use it for
>         defining constraint that need to be satisfied by provenance
>         applications. Further, given the current use of time with PE
>         definition and PE expression, it is more intuitive to state
>         the constraint as:
>
>         "The start time of a PE instance precedes the end time of a PE
>         instance" where time measurement is application-specific
>         requirement
>
>         3. Assuming, we go back to the original formulation of this
>         constraint in terms of time - If this is asserted as a
>         constraint to be satisfied by PROV compliant provenance
>         applications, it will make association of time value with PE a
>         necessary condition and not optional (as the current
>         definition of PE states).
>
>
>
>
>
>     -- 
>     Professor Luc Moreau
>     Electronics and Computer Science   tel: +44 23 8059 4487
>     <tel:%2B44%2023%208059%204487>
>     University of Southampton          fax: +44 23 8059 2865
>     <tel:%2B44%2023%208059%202865>
>     Southampton SO17 1BJ               email: l.moreau@ecs.soton.ac.uk
>     <mailto:l.moreau@ecs.soton.ac.uk>
>     United Kingdom http://www.ecs.soton.ac.uk/~lavm
>     <http://www.ecs.soton.ac.uk/%7Elavm>
>
>
>