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Re: simon:entity (or Identifiable)

From: Jim McCusker <mccusj@rpi.edu>
Date: Fri, 15 Jul 2011 13:46:26 -0400
Message-ID: <CAAtgn=Qp50FLSfA2DJybuJqNOxFCdEwaL==TOJkSkLNpVB8b8A@mail.gmail.com>
To: "Myers, Jim" <MYERSJ4@rpi.edu>
Cc: Luc Moreau <l.moreau@ecs.soton.ac.uk>, public-prov-wg@w3.org
On Fri, Jul 15, 2011 at 12:06 PM, Myers, Jim <MYERSJ4@rpi.edu> wrote:
>> Being able to describe what the entity "looks like" at the time the
>> provenance was recorded.
>> My understanding was that a BOB was something like a named graph,
> graph
>> literal (http://webr3.org/blog/semantic-web/rdf-named-graphs-vs-graph-
>> literals/),
>> or information artifact similar to iao:Dataset. The Bob would then
> have
>> content that described, in some way, the entity in question.
>> Hence the Bob being a description of an entity's state.
> Do you distinguish 'description of an entity' from 'description of an
> entity's state'? I get the sense that you are not using state in the
> same sense of 'a more stateful view of' that is driving the discussion
> of entity versus entity-state in the IVPof debates.

Any description of an entity will occur with an entity in a particular
state, and so two are the same.

>> If it is possible to know, there should be assertions on the BOB
> itself that say
>> which entity the BOB is describing. Ideally, this is a URI of
> something that's
>> referenced within the BOB.
> I'm hoping someone will chime in on this - I agree we need to connect
> the idea of a bob with the entity, but I could see implementing that as
> a link (as you say) or by saying that my entity's class is a subtype of
> Bob (hence there's only one URL for the Bob and the entity).

But that's clearly wrong, since Bobs only describe the state of an
entity at one point/span of time and context. If the same entity is
observed again, and a new Bob is created that describes the state
differently, then there's nothing to tie it down. I'm guessing that by
saying there is no referable entity outside of the Bob, then you can
just make Bobs all the way down. But there would be no grounding to
non-provenance resources in this case.

The Bob is the description of something based on its state, the Entity
is that something. A description of a thing is not the thing itself.
Within the context of information systems, one can say that
http://tw.rpi.edu/instances/JamesMcCusker is me. If you were to
download the RDF from that URL that would contain a description of me
within the context of RPI. The graph literal behind
http://tw.rpi.edu/instances/JamesMcCusker is one description (that can
change over time), and can be given an identifier using a graph digest
[1], guaranteeing that we always talk about the same graph. But that
graph is not me, even though the URI that returns it stands in for me
in the semantic web.

[1] http://citeseerx.ist.psu.edu/viewdoc/download?doi=

Jim McCusker
Programmer Analyst
Krauthammer Lab, Pathology Informatics
Yale School of Medicine
james.mccusker@yale.edu | (203) 785-6330

PhD Student
Tetherless World Constellation
Rensselaer Polytechnic Institute
Received on Friday, 15 July 2011 17:49:27 UTC

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