# RE: Bobs, IVP and time intervals

From: Myers, Jim <MYERSJ4@rpi.edu>
Date: Thu, 14 Jul 2011 12:14:05 -0400
Message-ID: <B7376F3FB29F7E42A510EB5026D99EF2053FFD91@troy-be-ex2.win.rpi.edu>
To: Stephan Zednik <zednis@rpi.edu>, Luc Moreau <L.Moreau@ecs.soton.ac.uk>
CC: <public-prov-wg@w3.org>
```I think this is a good argument for why we're really not talking about
things and states - we want two instances of something with the same
state to be different bobs if they have different provenance.
"Something-in-state-x" is just a shorthand for the more restrictive
notion that adds that each entry of something into state X is a unique
bob.

That might suggest a way to avoid having to talk explicitly about time
and still keep the notion we're all agreeing to that each occurrence of
something in a state is a separate bob - two bobs are not the same if
they don't have the same provenance which would then imply that bobs
existing over different time intervals must also be different because
they could not have been produced the same way (mistakes and open world
issues aside).

Jim

From: public-prov-wg-request@w3.org
[mailto:public-prov-wg-request@w3.org] On Behalf Of Stephan Zednik
Sent: Thursday, July 14, 2011 11:29 AM
To: Luc Moreau
Cc: public-prov-wg@w3.org
Subject: Re: Bobs, IVP and time intervals

On Jul 14, 2011, at 9:07 AM, Luc Moreau wrote:

Hi Stephan and Stephen

It's a good point that we need to capture.

So, "Luc in Boston" may correspond to many time intervals, corresponding
to my various trips to Boston.

We indicated the properties are not intended to be complete, and here,
this set of properties "Luc in Boston" does not identify which precise
visit we refer to.

However, each instance of Luc in Boston will have its own identity.

Yes.  Lets bring up an example scenario so we have something more visual

I've been thinking of what we called bob at the F2F1 as applying to a
continuous time interval which is a subset of the referenced entity's
continuous time interval for which some contextully-important mutable
characteristics of the referenced entity are held to immutable.

|<------------------------------------ Physical Object A
Exists--------------------------------------------------------|

|<----- A OwnedBy Person B--->O<---A OwnedBy Person C------>O<---A
OwnedBy Person D--->|

O is a ProcessExecution by which ownership of Physical Object A changes.
Agents involved in the ProcessExecution may include the selling and

In my simple diagram above, Person D could sell Object A back to Person
B at some point in time, and the two bobs that represent "A OwnedBy
Person B" would have their own identity because represent different time
intervals.

--Stephan

Regards,
Luc

On 07/14/2011 04:00 PM, Stephan Zednik wrote:

On Jul 14, 2011, at 8:51 AM, Cresswell, Stephen wrote:

Does a bob describe an entity over some continuous time interval?

This description matches well with how I have been interpreting bob.

--Stephan

--
Professor Luc Moreau
Electronics and Computer Science   tel:   +44 23 8059 4487
University of Southampton          fax:   +44 23 8059 2865
Southampton SO17 1BJ               email: l.moreau@ecs.soton.ac.uk
United Kingdom                     http://www.ecs.soton.ac.uk/~lavm

```
Received on Thursday, 14 July 2011 16:16:02 UTC

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