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RE: PROV-ISSUE-35: Section 4: How one would know that two BOBs are characterizations of the same entity? [Conceptual Model]

From: Myers, Jim <MYERSJ4@rpi.edu>
Date: Mon, 25 Jul 2011 13:48:39 -0400
Message-ID: <B7376F3FB29F7E42A510EB5026D99EF205468B77@troy-be-ex2.win.rpi.edu>
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 GMT

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