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

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 16:57:38 UTC