Re: PROV-ISSUE-454 (key across relations/objectss): can the same identifier be used for different relations objects [prov-dm-constraints]

as I was writing disjointness constraints, I also added activity/entity 
disjointness constraint.
I am not sure it is at the right place.

http://dvcs.w3.org/hg/prov/raw-file/default/model/prov-constraints.html#entity-activity-disjoint


Luc


On 07/19/2012 10:43 AM, Luc Moreau wrote:
> Hi all,
>
> I tried to formulate a constraint to express this.
>
> http://dvcs.w3.org/hg/prov/raw-file/default/model/prov-constraints.html#key-relation2
>
> Thoughts?
>
> Luc
> On 07/18/2012 10:57 AM, James Cheney wrote:
>> HI,
>>
>> Again, I don't see the need for an explicit issue about this.
>>
>> There is currently no constraint enforcing disjointness among 
>> different kinds of things/relations.  I see no particular reason to 
>> add one (and make implementation harder), unless there is clear 
>> consensus that violating such constraints is always nonsensical (and 
>> that this isn't detected by other constraints).
>>
>> We (I thought) want to allow for the possibility that something is 
>> both an agent and an entity, or both an agent or an activity, or 
>> other combinations.  One could then state that something influences, 
>> generates, uses itself etc., but this will just violate ordering 
>> constraints that we already have.
>>
>> I agree it seems nonsensical to allow overlap between different 
>> relations, and if so then someone needs to write constraints that do 
>> this.
>>
>> Constraints of the form "if hyp1 .... hypn then FALSE" (i.e., a given 
>> conjunctive pattern is impossible" are straightforward to handle: we 
>> just handle all the other inferences and constraints first, then 
>> check that the normal form does not have any of the forbidden 
>> patterns.  (The irreflexivity and asymmetry inferences for 
>> specialization already do this implicitly.)
>>
>> --James
>>
>> On Jul 18, 2012, at 10:39 AM, Tom De Nies wrote:
>>
>>> The only problem I see with allowing it, is when using influencedBy.
>>>
>>> With influence you'd be allowed to assert this:
>>>
>>> agent(a1)
>>> activity(a1)
>>> influencedBy(a1,a1)
>>>
>>> - Tom
>>>
>>> 2012/7/18 Provenance Working Group Issue Tracker 
>>> <sysbot+tracker@w3.org <mailto:sysbot+tracker@w3.org>>
>>>
>>>     PROV-ISSUE-454 (key across relations/objectss): can the  same
>>>     identifier be used for  different relations objects
>>>     [prov-dm-constraints]
>>>
>>>     http://www.w3.org/2011/prov/track/issues/454
>>>
>>>     Raised by: Luc Moreau
>>>     On product: prov-dm-constraints
>>>
>>>
>>>     We have the following two uniqueness constraints.
>>>
>>>     http://dvcs.w3.org/hg/prov/raw-file/default/model/prov-constraints.html#key-object
>>>     http://dvcs.w3.org/hg/prov/raw-file/default/model/prov-constraints.html#key-relation
>>>
>>>     It is not clear to me if
>>>
>>>     entity(e123)
>>>     agent(e123)
>>>
>>>     are acceptable. (To me, they should be, since we don't state the
>>>     set of agents to be disjoint from any other set)
>>>
>>>     Likewise, can we write
>>>
>>>     used(event1234,a1,e1,attrs1)
>>>     and
>>>     wasGeneratedBy(event1234,e2,a2,attrs2)
>>>
>>>     Probably not.
>>>     Note: if we allow the two above, then I am not sure that strict
>>>     ordering is wise in ordering constraints.
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>> The University of Edinburgh is a charitable body, registered in
>> Scotland, with registration number SC005336.
>
> -- 
> 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 Kingdomhttp://www.ecs.soton.ac.uk/~lavm
>
>
>

-- 
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