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

Hi Luc,

Yes. I think that's what we wanted at least as a short cut.

But can I do this?:

Webpage:
http://www.example.com/webpage

entity(http://www.example.com/webpage, [])

entity(http://www.example.com/webpage, [createdOn="June 4, 1998])


I think this is not allowed in the approach in the PROV-DM


You would have to do:

entity(http://www.example.com/webpage, [])

entity(http://www.example.com/webpage/June41998, [createdOn="June 4, 1998])

wasComplementOf(http://www.example.com/webpage/June41998, 
http://www.example.com/webpage)


This means in essence you do end up minting urls for provenance, right?
Paul


Luc Moreau wrote:
> Hi Paul,
> Yes, that's what the group wanted, I believe.
> Luc
>
> On 12/06/2011 05:35 PM, Paul Groth wrote:
>> Hi Luc,
>>
>> Hmm, I think I remember this now..... so everything can be an entity
>> record as soon as you type it as such.
>>
>> For example if I have a webpage:
>>
>> http://www.example.com/webpage
>>
>> It becomes an entity record, as soon as I do:
>>
>> entity(http://www.example.com/webpage, [])
>>
>> Is that a correct interpretation?
>>
>> Paul
>>
>>
>>
>>
>> Luc Moreau wrote:
>>> Hi Paul,
>>>
>>> So, OK, we could mint identifiers for entity record
>>>
>>>              entity(<a minted identifier here>, [ex:param="a",
>>> ex:port="foo"])
>>>
>>> (Which by the way is what OPM does.)
>>>
>>> How do you refer to the entity now? We don't know what this record is
>>> about.
>>>
>>> Luc
>>>
>>> On 12/06/2011 05:11 PM, Paul Groth wrote:
>>>> 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 17:51:06 UTC