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

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
>
>
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