W3C home > Mailing lists > Public > public-prov-wg@w3.org > September 2012

Re: PROV-ISSUE-471 (wrong-wasAttributedTo-constraints): wasAttributedTo constraints not sensical [prov-dm-constraints]

From: Paul Groth <p.t.groth@vu.nl>
Date: Mon, 3 Sep 2012 17:45:04 +0100
Message-ID: <CAJCyKRo4xkKMYZ4ieaz+L-QxuHO_=2vWFAO5fHn+2GDj7k9HGw@mail.gmail.com>
To: Stian Soiland-Reyes <soiland-reyes@cs.manchester.ac.uk>
Cc: Luc Moreau <l.moreau@ecs.soton.ac.uk>, "public-prov-wg@w3.org" <public-prov-wg@w3.org>
Hi,

We have made the case before that we want the constraints to help
guide people in the right direction. In particular, we have talked
about breaking activities down so that they represent what actually
occurred.

I think the same argument applies in this case. The agent should exist
before the entity.

If it does not, you can break down the description into constituent parts.

Paul


On Mon, Sep 3, 2012 at 5:09 PM, Stian Soiland-Reyes
<soiland-reyes@cs.manchester.ac.uk> wrote:
> On Mon, Sep 3, 2012 at 2:53 PM, Luc Moreau <l.moreau@ecs.soton.ac.uk> wrote:
>>
>>
>> I suggest the constraints becomes as follows:
>>
>> IF wasAttributedTo(_at;e,ag,_attrs) and
>> wasInvalidatedBy(invE;e,_a1,_t1,_attrs1) and
>> wasGeneratedBy(genAg;ag,_a1,_t1,_attrs1) THEN genAg precedes invE
>
> Although this laxer constraint would still be 'true', I wonder then
> about the point of this:
>
>> Inference 13 (attribution-inference)
>> IF wasAttributedTo(_att; e,ag,_attrs) THEN there exist a, _t, _gen, _assoc, _pl, such that wasGeneratedBy(_gen; e,a,_t,[]) and wasAssociatedWith(_assoc; a,ag,_pl,[]).
>
> If I assume for the argument that wasAttributedTo also covers any kind
> of ownership (which as you know I don't approve of ;) ), then I
> struggle with the above inference, as this forces the agent to also be
> involved with the *generation* of that entity. If I buy a car, then
> yes, I might be involved in the "purchasing" activity, which you can
> say is what generated the StiansCar entity. (which lives for as long
> as it has the characteristic of being owned by me -  note that this
> sounds more like attributes and entity characterisation) - but is this
> true for any kind of ownership? If I inherit a massive castle, or I
> have received in the mailbox (in a house I have just moved in to) a
> 2013 calendar from a local shop, am I then 'attributed to' the castle
> or the calendar, and required to be associated with the activity that
> made me the owner?
>
>
> Should it then not a requirement be for the agent to be involved with
> the activity before the entity was generated? Your proposed constraint
> (as quoted above) would allow the agent to come to life just before
> the invalidation of the entity, get a brief ownership (duration of
> which we don't know), and then let the entity invalidate.  It is OK
> with the wasAssociatedWith-ordering rule as long as the activity that
> generated the entity is still running at this point, for instance that
> the factory is still making cars or the postman still doing his
> deliveries.
>
> This sounds a bit odd for me. It should be one way or the other.  The
> time ordering constraints should cover, ideally, exactly what is
> required, not allow various scenarios we do not intend to be legal.
>
> If the ownership is true for the whole lifetime of the entity (which I
> would presume!), then that is an attribute that I would see in the
> entity, not as a separate statement. If it is still to be said as a
> statement, then we need boundary conditions on both sides, just like
> we say attributes are valid all the way from the generation till
> invalidation.
>
>
> My proposal is to keep the current definition:
>
>> Constraint 50 (wasAttributedTo-ordering)
>> IF wasAttributedTo(_at; e,ag,_attrs) and wasGeneratedBy(gen1; ag,_a1,_t1,_attrs1) and wasGeneratedBy(gen2; e,_a2,_t2,_attrs2) THEN gen1 precedes gen2.
>> IF wasAttributedTo(_at; e,ag,_attrs) and wasStartedBy(start; ag,_e3,_a3,_t3,_attrs3) and wasGeneratedBy(gen; e,_a4,_t4,_attrs4) THEN start precedes gen.
>
> (Note: There are two rules, depending on the agent being an entity or
> an activity. We can't time-order non-entity, non-activity agents).
>
>
> This says that the agent must be involved in the generation of the
> entity. We do not have time stamps on association, but the intention
> is that he was associated before entity generation. This must be true
> - from the above - also for the case of ownership.
>
> The agent is not required to be involved with its invalidation, but we
> know that the the invalidation must be after his generation, because
> of the combination of constraint generation-precedes-invalidation and
> wasAttributedTo-ordering.
>
>
> --
> Stian Soiland-Reyes, myGrid team
> School of Computer Science
> The University of Manchester
>



-- 
--
Dr. Paul Groth (p.t.groth@vu.nl)
http://www.few.vu.nl/~pgroth/
Assistant Professor
- Knowledge Representation & Reasoning Group |
  Artificial Intelligence Section | Department of Computer Science
- The Network Institute
VU University Amsterdam
Received on Monday, 3 September 2012 16:45:35 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 3 September 2012 16:45:36 GMT