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

From: Stian Soiland-Reyes <soiland-reyes@cs.manchester.ac.uk>
Date: Thu, 6 Sep 2012 11:36:52 +0100
Message-ID: <CAPRnXtk_97bMwm0s2ewB9MDOWbTqBuUCRAef1y0923DAQyUksw@mail.gmail.com>
To: Luc Moreau <l.moreau@ecs.soton.ac.uk>
Cc: public-prov-wg@w3.org
Looks good! :)

On Tue, Sep 4, 2012 at 12:33 PM, Luc Moreau <l.moreau@ecs.soton.ac.uk> wrote:
>
> Hi Stian,
>
> Figure 6b updated to reflect wasAttributed_ordering, with your stricter
> ordering constraint.
>
> Luc
>
>
> On 03/09/12 17:09, Stian Soiland-Reyes 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
>
>
> --
> 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
>



-- 
Stian Soiland-Reyes, myGrid team
School of Computer Science
The University of Manchester
Received on Thursday, 6 September 2012 10:37:42 GMT

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