- From: Myers, Jim <MYERSJ4@rpi.edu>
- Date: Mon, 25 Jul 2011 13:48:39 -0400
- To: Khalid Belhajjame <Khalid.Belhajjame@cs.man.ac.uk>, Paolo Missier <Paolo.Missier@ncl.ac.uk>
- CC: <public-prov-wg@w3.org>
If Bobs represent characterized things (PROV issue 30 discussion and the model doc), then why would there ever be a case where we couldn't represent A by Abob and talk about B1 and B2 referring to ABob or both being viewsofSameBob(b1,b2) to avoid defining A_bob? I guess I'm pushing to separate the question of whether this is a direct binary relationship versus referencing a third thing from the question of what that third thing is. Jim > -----Original Message----- > From: public-prov-wg-request@w3.org [mailto:public-prov-wg- > request@w3.org] On Behalf Of Khalid Belhajjame > Sent: Monday, July 25, 2011 1:04 PM > To: Paolo Missier > Cc: public-prov-wg@w3.org > Subject: Re: PROV-ISSUE-35: Section 4: How one would know that two BOBs > are characterizations of the same entity? [Conceptual Model] > > > Hi Paolo, > > On 25/07/2011 13:27, Paolo Missier wrote: > > Khalid, Jim > > > > the issue that lurks behind this discussion is, once again, that of > > identity in the space of characterized entities (C-entities). The > > draft doc avoids talking about identity and instead mentions > > /identifiers/ which belong in the model. These identifiers have more > > of a technical than a semantic meaning, i.e., they exist so one can > > refer to, and link across, different Bobs in the model. > > > > With this, see if I can summarize that we have: > > > > - Khalid suggests to introduce sameEntityAs as an equivalence relation > > in the C-entities space, and then admit axiomatic assertions of the > > form > > (1) sameEntity(b1,b2) > > where b1, b2 are (identifiers of) two Bobs in the model. > > > > - Jim suggests that it should be possible to assert, also axiomatically: > > (2) "Bob b1 refers to entity A", "Bob b2 refers to entity A" > > > > The main difference is that assertions (2) require us to mention A, > > which lives in C-Entity space, and so far we have not made any > > provision to do so. (1) has not such requirement. > > That is exactly why I thought of (1) instead of (2), this way we don't have to > include a new term to the vocabulary. > > Thanks, khalid > > > > > If you use the Royal Society example > > http://dvcs.w3.org/hg/prov/raw-file/default/model/ProvenanceModel.html > > #IVP-of > > for reference, this means: > > > > - using (2) I need to be able to say "Royal Society" somewhere in the > > language > > - using (1) I don't, but then I never really know what the BOBs refer to. > > > > To me it boils down to whether we ever need to mention "Royal Society" > > or we are happy to say "b1, b2 refer to the same C-entity > > which-shall-not-be-named". > > > > Notes: > > - if we have (2), then (1) follows. > > - (1) is sufficient to reason about IVP-of relations, i.e. using > > entity resolution algorithms (which, as Jim points out, are outside > > the PIL language). > > > > -Paolo > > > > > > On 7/21/11 9:11 PM, Jim McCusker wrote: > >> In the simple case, if a BOB refers to Entity A (for instance, as a > >> URI), and another BOB also refers to Entity A, then the BOBs refer to > >> the same Entity. > >> > >> The complex case, where we try to resolve the entities by examining > >> the BOBs closely, I think is outside of the PIL, and can be > >> determined by applications using whatever algorithms they think are > important. > >> > >> Jim > >> > >> On Thu, Jul 21, 2011 at 3:39 PM, Khalid Belhajjame > >> <Khalid.Belhajjame@cs.man.ac.uk> wrote: > >>> On 21/07/2011 20:20, Luc Moreau wrote: > >>> > >>> Hi Khalid, > >>> Can you expand on this? What would it help us to achieve? > >>> > >>> At F2F1, some mentioned "turtle all way down" to refer to the idea > >>> that we are not trying to make a distinction between an entity and > >>> its state (as we used to say then). > >>> This would translate into the fact that we only have characterized > >>> entities ... > >>> and are not trying to distinguish an entity from a characterized > >>> entity. > >>> > >>> Can you explain what benefits you see in distinguishing entity from > >>> characterized entity? > >>> > >>> So, does it mean in the example, you would say that e1 is same > >>> entity as e2? > >>> Potentially, this could be captured by (the very rough) definition > >>> of version. > >>> > >>> Yes, possibly, I actually first thought that "isRevisionOf" can be > >>> used, but I think it poses stronger condition that what is needed by > >>> "sameEntity". > >>> > >>> Regarding your question about the benefits. I think, having > >>> "sameEntity()" > >>> can be used in the definition of IVPof: > >>> Specifically, in page 10, it is stated that: > >>> > >>> "An assertion "B is an IVP of A" holds over the temporal > >>> intersection of A and B, only if: > >>> > >>> if a mapping can be established from an attribute X of B to an > >>> attribute Y of A, then the values of A and B must be consistent with > >>> that mapping B has some attribute that A does not have" > >>> > >>> I think, if "sameEntity" exists then it can be used as a third > >>> condition, to make sure that A and B refers to the same entity, > >>> otherwise one cannot be an IVPof the other. > >>> > >>> Also, given a BOB bi, a user may be interested in tracing the > >>> history of all the BOBs that were used to derive b1 and that refer > >>> to the same entity. > >>> In other words, the query here is give me the history of the entity > >>> that bi refers to. > >>> > >>> khalid > >>> > >>> > >>> > >>> Luc > >>> > >>> On 21/07/2011 20:06, Provenance Working Group Issue Tracker wrote: > >>> > >>> PROV-ISSUE-35: Section 4: How one would know that two BOBs are > >>> characterizations of the same entity? [Conceptual Model] > >>> > >>> http://www.w3.org/2011/prov/track/issues/35 > >>> > >>> Raised by: Khalid Belhajjame > >>> On product: Conceptual Model > >>> > >>> > >>> Do we need a mean to specify that two BOB are characterizations of > >>> the same entity? > >>> > >>> In the initial draft, I think that the editors intentionally avoided > >>> defining the term "entity" as part of the vocabulary. I don't > >>> suggest defining that term, but having a means by which one would > >>> know that two Bobs are characterizations, possibly different, of the > >>> same entity, e.g., using an assertion like "sameEntity(bob1, bob2)". > >>> > >>> I think this will be useful, amongst other things, in the definition > >>> of IVPof. > >>> > >>> Khalid > >>> > >>> > >>> > >>> > >>> > >>> > >> > >> > > > > >
Received on Monday, 25 July 2011 17:49:42 UTC