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Re: PROV-ISSUE-29 (mutual-iVP-of): can two bobs be mutually "IVP of" each other [Conceptual Model]

From: Timothy Lebo <lebot@rpi.edu>
Date: Mon, 2 Apr 2012 08:40:31 -0400
Cc: James Cheney <jcheney@inf.ed.ac.uk>, Paul Groth <p.t.groth@vu.nl>, "public-prov-wg@w3.org" <public-prov-wg@w3.org>
Message-Id: <04089ED8-CE83-4386-97DE-EBC6A22B2B5D@rpi.edu>
To: Luc Moreau <L.Moreau@ecs.soton.ac.uk>

On Apr 2, 2012, at 5:27 AM, Luc Moreau wrote:

> Hi James,
> 
> 
> 
>> 
>> I see absolutely no point to or motivation for allowing an entity to refer to more than (or less than) one thing.  
>> 
> So, still trying to understand, if it's the case, what is the point of talking about things?
> Shouldn't the English definition of these concepts be expressed without the term 'thing'?

+1


-Tim


> 
> Luc
> 
>  
>> --James
>> 
>> On Apr 1, 2012, at 8:20 PM, Luc Moreau wrote:
>> 
>>> 
>>> 
>>> 
>>> On 1 Apr 2012, at 12:12, "Paul Groth" <p.t.groth@vu.nl> wrote:
>>> 
>>>> My answers:
>>>> 
>>>> 1. An entity refers to one thing that thing may or may not be identified
>>> 
>>> 
>>> At a given point in time, possibly, but is it the case when time changes?
>>> 
>>> Can't recall the exact detail, but the 'customer on the third chair' may be the
>>> woman in red at t1 and the man in black at t2. Can't it?
>>> 
>>> 
>>> Luc
>>> 
>>> 
>>>> 
>>>> 2. Specialization thus is defined in terms of 1
>>>> 
>>>> Paul - not a specialization/alternator guru 
>>>> 
>>>> On Apr 1, 2012, at 9:46, Luc Moreau <l.moreau@ecs.soton.ac.uk> wrote:
>>>> 
>>>>> Hi all specializationOf/alternateOf gurus,
>>>>> 
>>>>> The current definition of alternateOf does not allow us to decide whether James's or my interpretation
>>>>> is right.  The question is essentially: does an entity refer to one and only one thing or not.
>>>>> 
>>>>> So, 
>>>>> 
>>>>> 1. What is intended?
>>>>> 2. How do we clarify definitions?
>>>>> 
>>>>> Cheers,
>>>>> Luc
>>>>> 
>>>>> 
>>>>> On 31/03/2012 15:46, James Cheney wrote:
>>>>>> 
>>>>>> On 30/03/12 10:01, Luc Moreau wrote:
>>>>>>> 
>>>>>>> 
>>>>>>> Dear all,
>>>>>>> 
>>>>>>> I am getting conflicting messages on this topic!
>>>>>>> 
>>>>>>> James has listed some properties derived from the semantics
>>>>>>> http://lists.w3.org/Archives/Public/public-prov-wg/2012Mar/0470.html
>>>>>>> But not all of them seem to be aligned with what we are reading on this thread.
>>>>>>> 
>>>>>>> So, I started drafting a section in prov-dm part II listing the properties of these relations [1].
>>>>>>> 
>>>>>>> I am proposing to justify each property either by reasoning based on its definition,
>>>>>>> or by a counter-example.
>>>>>>> 
>>>>>>> Your suggestions are needed to help us complete this section.  
>>>>>>> 
>>>>>>> James, unless my reasoning is incorrect, I do not have transitivity for specializationOf.
>>>>>> 
>>>>>> Hi Luc,
>>>>>> 
>>>>>> Your reasoning (quoting from [1])  is:
>>>>>> 
>>>>>>> Specialization is not transitive. Indeed if specializationOf(e1,e2) holds, then there is some common thing, say e1-2 they both refer to. Likewise, if specializationOf(e2,e3) holds, then there is some common thing, say e2-3 they both refer to. It does not follow there is a common thing both e1 and e3 refer to.
>>>>>> 
>>>>>> In the WD3 formal semantics [2], I modeled entities-referring-to-things as a function thingOf : Entity -> Thing.  
>>>>>> 
>>>>>> Thus, if thingOf(e1) = e1-2 = thingOf(e2) and thingOf(e2) = e2-3 = thingOf(e3) then (by transitivity of equality) e1-2 = e2-3 and all three entities refer to the same thing, e1-2.
>>>>>> 
>>>>>> Of course, it is an assumption I made that an entity "refers to" exactly one thing.  If we want to allow entities to refer to multiple things, then the reasoning I give above fails, and specializationOf is not necessarily transitive.
>>>>>> 
>>>>>> --James
>>>>>> 
>>>>>> [1] http://dvcs.w3.org/hg/prov/raw-file/default/model/prov-dm-constraints.html#component4
>>>>>> [2] http://www.w3.org/2011/prov/wiki/FormalSemanticsWD3
>>>>>> 
>>>>>> The University of Edinburgh is a charitable body, registered in
>>>>>> Scotland, with registration number SC005336.
>>>>>>   
>> 
>> 
>> The University of Edinburgh is a charitable body, registered in
>> Scotland, with registration number SC005336.
>>   
> 
> -- 
> 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 Monday, 2 April 2012 12:41:19 GMT

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