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Re: complementOf -> viewOf: proposed text

From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
Date: Wed, 18 Jan 2012 14:47:41 +0000
To: "Myers, Jim" <MYERSJ4@rpi.edu>
CC: Paolo Missier <Paolo.Missier@ncl.ac.uk>, Paolo Missier <paolo.missier@newcastle.ac.uk>, Stian Soiland-Reyes <soiland-reyes@cs.manchester.ac.uk>, "public-prov-wg@w3.org" <public-prov-wg@w3.org>
Message-ID: <EMEW3|9ebfe8e1ed5c84cb055dddc665fc6621o0HEll08L.Moreau|ecs.soton.ac.uk|4F2133F5-C3B2-4A35-92D8-A7F4CA655B7A@ecs.soton.ac.uk>
Hi Jim

A simple English sentence seems to question seriously the model:

 One entity may be a characterisation for multiple things.

 Entity( e1, [ colour = blue ])

Indeed this characterise many things including 
 Tshirt-of-Luc-in-Boston-2011
And
  Luc-new-car-2012

How would that work with characterisation intervals (in 2011 and 2012)?
What would it mean for an activity to generate that?

It seems that this approach is restoring the attributes as characterising, which we voted against.



What maybe you mean is that the model does not specify exactly which thing an entity characterises ( in addition, the characterisation is not expected to be complete), but in theory there is one and only one thing.


Professor Luc Moreau
Electronics and Computer Science
University of Southampton 
Southampton SO17 1BJ
United Kingdom

On 18 Jan 2012, at 14:02, "Myers, Jim" <MYERSJ4@rpi.edu> wrote:

> Darn English - 
> Each entity represents one full characterization of some thing (and only one *Characterization* - they are unambiguous w.r.t. everything being asserted) -
> 
> While an entity is asserted to represent a characterization of one thing, it may characterize many things - paolo-in-the-chair characterizes paolo with his location fixed and it characterizes person-in-chair with the person fixed.
> Until processes occur that destroy paolo-in-the-chair, paolo-in-the-chair specializes both and they are alternates.
> 
> I'll try to respond about time again, but in short - I think we can/should frame the definitions in terms of events rather than time per se, and that this is necessary to make alternate work for use cases like Stian's. Sitting and standing events create/destroy paolo-in-the-chair... I have to think more, but one could potentially make alternate fully transitive by requiring us to create 'person-in-chair-with-name-paolo' as a specialization of person-in-chair and make this the alternateOf paolo-in-chair - they have the same lifetime and hence 'time'/differences in lifetime go away. Saying paolo and person-in-chair are alternates over some interval between the sitting and standing events seems like an alternate way to model that would cover the same ground - we'd have 'pseudotransitivity' (which I think can be defined clearly over intervals) but would need fewer specialized entities in the description...
> 
> Jim
> 
> 
>> -----Original Message-----
>> From: Paolo Missier [mailto:Paolo.Missier@ncl.ac.uk]
>> Sent: Wednesday, January 18, 2012 8:40 AM
>> To: Luc Moreau
>> Cc: Paolo Missier; Stian Soiland-Reyes; public-prov-wg@w3.org
>> Subject: Re: complementOf -> viewOf: proposed text
>> 
>> Luc
>> 
>> On 1/17/12 6:59 PM, Luc Moreau wrote:
>>> Hi Paolo, Stian
>>> 
>>> To answer the transitivity question, we need to answer a question. Can an
>> entity characterise different things? If yes, I agree transitivity does not
>> necessarily hold. If no, transitivity holds.
>> from Jim's earlier comprehensive message, I gather that the answer is not:
>>> each entity therefore  represents one full characterization  of some thing
>> (and only one - they are unambiguous w.r.t. everything being asserted) .
>> but also please see my reply to Jim, with the suggestion that temporal overlaps
>> ought to be reintroduced. But we've been there
>> before: entity records do not mention temporal validity. So if temporal
>> overlaps are an argument against transitivity in this case, then I believe the
>> best we can do is remove transitivity and do a bit of hand-waiving when asked
>> about it :-)
>> 
>> -Paolo
> 
Received on Wednesday, 18 January 2012 14:48:41 UTC

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