- From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
- Date: Tue, 06 Dec 2011 22:07:57 +0000
- To: Paul Groth <p.t.groth@vu.nl>
- CC: "public-prov-wg@w3.org" <public-prov-wg@w3.org>
Hi Paul, Response are interleaved. On 06/12/11 17:50, Paul Groth wrote: > 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 It is allowed, but the two records should be regarded as a single one, obtained by union of the two. See http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html#identified-entity-in-account and the example that follows. > > > 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? Yes, this is similar to section 8 of the prov-dm document. What is not entirely clear to me is how do we know that http://www.example.com/webpage is the identifier of the real stuff, whereas http://www.example.com/webpage/June41998 was minted . Luc > 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 >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >> >
Received on Tuesday, 6 December 2011 22:09:48 UTC