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

From: Satya Sahoo <satya.sahoo@case.edu>
Date: Wed, 11 Jan 2012 16:05:22 -0500
Message-ID: <CAOMwk6yBpgeftBrdZ_fzHr83u6F0V+RAf7HKjFGVPh=8joTMLg@mail.gmail.com>
To: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Cc: public-prov-wg@w3.org
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I agree that the points in this issue have either been superseded by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.



On Tue, Dec 20, 2011 at 11:38 AM, Luc Moreau <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<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<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
> 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<http://www.ecs.soton.ac.uk/~lavm>
Received on Wednesday, 11 January 2012 21:05:52 UTC

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