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Re: simon:entity (or Identifiable)

From: Khalid Belhajjame <Khalid.Belhajjame@cs.man.ac.uk>
Date: Sat, 16 Jul 2011 14:26:54 +0100
Message-ID: <4E21919E.40207@cs.man.ac.uk>
To: "Myers, Jim" <MYERSJ4@rpi.edu>
CC: Luc Moreau <l.moreau@ecs.soton.ac.uk>, public-prov-wg@w3.org, renear@illinois.edu
> People want to find bobs by their description (not just identifier) – 
> to me this means our model has to include the idea of properties. If 
> we punt and say that all means of discovering a particular bob – 
>  finding it based on its description to get to an ID, or using the ID 
> to learn something about it – is out-of-band, I don’t think we have a 
> usable standard. If there are alternatives to saying that bobs have 
> properties with values that keeps this functionality, let’s get them 
> on the table. (Do any of us think that pushing this functionality 
> out-of-band is OK?)

Yes, I agree. I actually asked a question in another thread on whether 
the notion of identity of a BOB is needed, since in general users will 
be interested in the (content of a) bob itself. Properties is one way of 
uncovering the content of a BOB, I was, however, more inclined to adopt 
the notion of "state" since it conveys the same meaning without 
requiring identifying the properties of a BOB.


> IVPof does have the notion that there is real correspondence between 
> the two bobs: B IVPof A. I think it is equally valid to talk about 
> that correspondence in terms of saying that these two bobs overlap in 
> some of the dimensions in which they are defined, or to say they 
> represent the same stuff (because there’s something in the overlapping 
> region of common dimensionality of these bobs). I see the idea of one 
> bob being a lower dimensional projection of another being the same 
> special case in which there are properties of A that are mutable that 
> are fixed in B. Our general case has to include cases where the bobs 
> are defined in terms of different coordinate systems over those 
> dimensions (so their properties do not match) as well as where A and B 
> overlap in some dimensions but each is also defined over some 
> dimension(s) that the other does not share. (When Allen Renear (U. 
> Illinois) visited recently, we had a fun discussion of the idea that 
> only one thing can be in the same place at the same time – dimensional 
> overlap as a way to define identity/equivalence. He brought up the 
> example of talking about a statue versus the bronze in a statue as 
> something that breaks this – I see this as a case where the bronze and 
> the statue are each defined in dimensions the other is not, which is 
> why we can’t see one as equivalent to or as a state of the other (not 
> a hierarchical case)).
> I think what that means in short is that if we try to describe 
> everything in terms of dimensions, we don’t get something 
> substantially simpler than we have now. TimBL’s model sounds simpler 
> because he’s describing a simple subset of what we need to model.
> Jim
> *From:*public-prov-wg-request@w3.org 
> [mailto:public-prov-wg-request@w3.org] *On Behalf Of *Luc Moreau
> *Sent:* Friday, July 15, 2011 7:56 AM
> *To:* public-prov-wg@w3.org
> *Subject:* Re: simon:entity (or Identifiable)
> Hi Ryan,
> It's exactly where we were about 8 weeks ago. Your proposal seems to 
> ignore
> many agreements this WG has reached. We were using the word "R" then.
> The reason why we moved into the direction of thing and IVP is that
> there is stuff out there that is changing. For provenance, we need
> something that didn't change from some perspective (or had some fixed
> value).
> For your proposal to work from my viewpoint, it needs to be more precise
> about what is identifiable. Is it a stuff or is it a state of a stuff?
> I note that all our discussions point to the fact that it is really
> hard to distinguish a stuff from its state, since it is very much a
> question of perspective.  Still, we need to be precise about what is
> identifiable. I think that the notion of properties associated with
> old:thing/f2f1:BOB is reasonable way of providing the necessary precision.
> Regards,
> Luc
> Regards,
> Luc
> On 15/07/2011 06:36, Ryan Golden wrote:
> With apologies to Simon for hijacking his namespace, I'd like to take 
> up Luc's suggestion to break off what he called the "simon:entity" 
> proposal from the earlier thread into a separate thread.
> Rationale
> --------------
> It should come as little surprise that some problems we are trying to 
> solve by our design have been faced before by others in different 
> contexts.  After poring over the thread between Simon, Jim and others, 
> I discovered a design issue discussion at 
> (http://www.w3.org/DesignIssues/Generic), published by TimBL, which 
> bears a _striking_ resemblance to the discussion we're having on 
> stuff, thing, entity, entity state, and bob.  While he does use the 
> "R" word in some of the discussion, he makes the key observation that 
> the identifiers we use every day have "multi-level genericity."  That 
> is to say, some identifiers are very specific ("Halley's comet, as 
> viewed from the Hubble telescope, on 1/1/2014, in JPG format"), others 
> more generic ("Halley's comet").  The Web design, he states, "should 
> not arbitrarily seek to constrain life in general for its own 
> purposes."  Neither should we, I would argue.
> Further, we may may make statements about "dimensions of genericity." 
> That is to say that a) in relation to the thing it identifies, an 
> identifier can be generic with respect to a particular dimension, 
> e.g., in relation to the real Halley's comet, the "Halley's comet" 
> identifier is generic with respect to time and content-type; and b) 
> one identified thing may be generic in relation to another identified 
> thing with respect to zero or more dimensions.  TimBL talks about the 
> relatively small number of dimensions of genericity for electronic 
> resources, whereas we are interested in the infinite number of 
> dimensions (i.e., all possible properties) over which identifiers and 
> things in the world (not just electronic resources) may vary.  The 
> idea of "dimensions of genericity" gives what I believe to be a nice 
> formulation for what we've been trying to discuss as "IVP of."  I 
> leave the remainder of this discussion to a separate thread, however 
> (please post any comments on this paragraph to that thread).
> If I fail to express some of TimBL's ideas adequately, I strongly 
> suggest you read the Design Note--it is brief and more well-written.
> Proposal
> -------------
> Given both elegant formulations, I would like to propose we conflate 
> the following concepts:
>     old:stuff
>     old:thing
>     f2f1:entity
>     f2f1:bob
>     f2f1:entity state
> Into a single concept:
>     simon:entity (alternate suggested name: "Identifiable")
> Which can be described as:
>    that which an identifier represents
> And, importantly for IVP of:
>    A simon:entity/Identifiable may exhibit a different level of 
> genericity in relation to another simon:entity/Identifiable with 
> respect to zero or more dimensions.
> --Ryan
Received on Saturday, 16 July 2011 13:27:34 UTC

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