- From: Timothy Lebo <lebot@rpi.edu>
- Date: Mon, 2 Apr 2012 08:33:32 -0400
- To: James Cheney <jcheney@inf.ed.ac.uk>
- Cc: Luc Moreau <L.Moreau@ecs.soton.ac.uk>, Paul Groth <p.t.groth@vu.nl>, "public-prov-wg@w3.org" <public-prov-wg@w3.org>
- Message-Id: <E45299BE-E357-4ACD-9CA8-CA6CF2D928E9@rpi.edu>
On Apr 2, 2012, at 4:58 AM, James Cheney wrote: > Hi Luc, > > The point of having each Entity mapped to a (unique) Thing in the semantics is to avoid this kind of confusion. > ... > > I see absolutely no point to or motivation for allowing an entity to refer to more than (or less than) one thing. +10 -TIm > > --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.
Received on Monday, 2 April 2012 12:34:12 UTC