Re: PROV-ISSUE-183 (prov-dm-identifiers): identifiers in prov-dm [prov-dm]

So I always thought that you could mint identifiers for entity records 
but you didn't have to and we supported that.

But maybe that's my head inserting text where it shouldn't have been....

Paul

Luc Moreau wrote:
> ... the conclusion issue ;-)
>
> No, we have no formal decision on this.
>
> We wrote this in the prov-dm document a long time ago (before fpwd), and
> we have
> been refining it over time.
>
> I think it's an inevitable consequence of two key decisions:
> - distinguishing entities (in the world) from entity records (in the
> provenance)
> - not mandating the minting of new URIs for entity records
>       (no formal decision on this, but I think we have support for it, since
>        we want to minimize the effort to generate provenance)
>
> Luc
>
>
> On 12/06/2011 04:56 PM, Paul Groth wrote:
>> Hi Luc,
>>
>> Do you have a pointer to wear we reached the consensus about the dual
>> role of identifiers?
>>
>> Thanks,
>> Paul
>>
>> Provenance Working Group Issue Tracker wrote:
>>> PROV-ISSUE-183 (prov-dm-identifiers): identifiers in prov-dm
>>> [prov-dm]
>>>
>>> http://www.w3.org/2011/prov/track/issues/183
>>>
>>> Raised by: Luc Moreau On product: prov-dm
>>>
>>>
>>> Hi,
>>>
>>> It think that it is now time to have a proper debate about
>>> identifiers in prov-dm since comments are regularly expressed about
>>> them. I have raised this issue about this topic so that we can track
>>> the conversation properly. Our hope is to reach consensus on this
>>> topic by the time of the third working draft.
>>>
>>> First, in the fpwd, there was a mention of "qualified identifier"
>>> (appearing in a note see [1]).  We have removed this term from the
>>> second working draft.
>>>
>>> Second, the complementarity record now explicitly allows for linking
>>> entity records across accounts. Its syntax allows for two accounts to
>>> be named.
>>>
>>> Third, identifiers for entities in prov-dm have a dual role [3]. An
>>> entity has got an id (typically given by an application). An entity
>>> record --- i.e. what we say about an entity in a provenance record
>>> --- also has an id. There is a consensus that we shouldn't mint
>>> identifiers for provenance records. Hence, the identifier of the
>>> entity record is defined to be the same as the identifier of the
>>> entity.
>>>
>>> The consequence of this is that two entity records in different
>>> accounts may have the same identifier: they may say different things
>>> about the same entity.  For example, the document ex:doc was
>>> generated by latex in account1, while in account 2, ex:doc is
>>> described to be the result of a survey of a field by different
>>> authors.
>>>
>>> This explains why we needed the complementarity record to name the
>>> accounts as well. This assumes that account names need to be named
>>> uniquely (see [4]).
>>>
>>> So, entity records identifiers are scoped to accounts.  Note, I said
>>> entity *records*, not entities. Hence, we are not breaking the
>>> semantic web approach: an entity is a resource and is denoted by a
>>> URI, and this remains true in all accounts. (I guess that from a
>>> semantic web perspective we are not looking at a provenance record as
>>> resource, since we don't have a global URI to name it.) Finally, we
>>> allow for accounts to be nested hierarchically; this fits nicely with
>>> abstraction in provenance records. Again, see [4].
>>>
>>> Can you express your views about this approach, as currently defined
>>> in the second draft of prov-dm?
>>>
>>> Thanks, Luc
>>>
>>> [1]
>>> http://www.w3.org/TR/2011/WD-prov-dm-20111018/#expression-identifier
>>> [2]
>>> http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#record-complement-of
>>>
>>>
>>>
>> [3]
>> http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#record-Entity
>>
>>> [4]
>>> http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#record-Account
>>>
>>>
>>>
>>>
>>>
>

-- 
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
VU University Amsterdam

Received on Tuesday, 6 December 2011 17:12:37 UTC