W3C home > Mailing lists > Public > public-prov-wg@w3.org > January 2012

RE: complementOf -> viewOf: proposed text

From: Cresswell, Stephen <stephen.cresswell@tso.co.uk>
Date: Thu, 19 Jan 2012 11:20:25 -0000
Message-ID: <F22D0BFCDD4DDC44B92C4E24D751CB93D6C62A@W3EXC017023.theso.co.uk>
To: "Paolo Missier" <Paolo.Missier@ncl.ac.uk>, "Luc Moreau" <L.Moreau@ecs.soton.ac.uk>
Cc: <public-prov-wg@w3.org>

I think that if someone asserts alternateOf, then they have to live with
not being able to make any inferences from it.  If they want to give
more detail by saying it with specializationOf, it is possible to do the
inference and derive alternativeOf relations.

This depends on the identity:
alternativeOf(a, b) == exists (c) : 
   specializationOf(a,c) and 
   specializationOf(b,c)

... which has been removed for reasons which I don't understand (the
things-and-entities vs. entities-all-the-way-up discussion).  We can
practically use the identity to do the inference at least in one
direction:
alternativeOf(a, b) <== exists (c) : 
   specializationOf(a,c) and 
   specializationOf(b,c)

(I think this can be expressed in OWL2 by defining an inverse property
for specializationOf and using a property chain).

It then seems reasonable to me that if someone wants to be able to make
inferences about alternateOf, then instead of asserting
alternateOf(A,B), they should instead make the two primitive assertions:
 specializationOf(A,C)
 specializationOf(B,C)

... which entails alternateOf(A,B), but also names the entity C, which
gives extra information about the respect in which A and B are
alternatives (c.f. the 3-place alternateOf which Luc suggested earlier
in this thread).  Given the transitivity of specializationOf, this
allows all reasonable alternativeOf relations to be derived.  It can
give clusters of mutually alternateOf entities, which are (direct or
indirect) specialisations of a common entity.  Hence we can get the
desired inferences without making alternateOf transitive in general.

Stephen Cresswell

> -----Original Message-----
> From: Paolo Missier [mailto:Paolo.Missier@ncl.ac.uk]
> Sent: 19 January 2012 09:54
> To: Luc Moreau
> Cc: Graham Klyne; Stian Soiland-Reyes; Paolo Missier; public-prov-
> wg@w3.org
> Subject: Re: complementOf -> viewOf: proposed text
> 
> yes.
> 
> I will do that now
> 
> -Paolo
> 
> On 1/19/12 9:52 AM, Luc Moreau wrote:
> > Hi Graham, Paolo, all
> >
> > Given this,  and to allow us to progress on the document, can we,
for
> > now, remove
> > the transitivity property, and add a note in the document, stating
that
> > the transitivity property is still
> > under investigation?
> >
> > Cheers,
> > Luc
> >
> > On 01/19/2012 09:27 AM, Graham Klyne wrote:
> >> Hmmm... this is starting to feel to me like a philosophical
rathole.
> >>
> >> I think we may be muddling things and roles, as maybe illustrated
by
> >> your:
> >>
> >>    So similarly I would not like to conclude alternateOf(Bush,
Obama)
> >>
> >> This feels like a replay of the old Fregian "Hesperus and
Phosporus"
> >> sense and reference discussion.
> >>
> >> All this complexity is leading me to a view that while transitivity
of
> >> alternativeOf may be appealing at some levels of intuition, it may
> >> carry too many traps and, absent a compelling requirement, we'd be
> >> better to leave it.
> >>
> >> Which I think is what Paolo is suggesting.
> >>
> >> #g
> >> --
> >>
> >> On 18/01/2012 08:55, Stian Soiland-Reyes wrote:
> >>> On Tue, Jan 17, 2012 at 18:01, Graham Klyne<GK@ninebynine.org>
> wrote:
> >>>>> alternateOf(paoloInCafe, customerOnRedChair)
> >>>>> alternateOf(stianInCafe, customerOnRedChair)
> >>>> Hmmm... I'm not sure these actually match my intuition about
> >>>> alternateOf;
> >>>> i.e. that they're both versions of some real-world thing.  What
> >>>> real-worlkd
> >>>> thing would that be?
> >>> It would be something like the atoms of the living person who sits
> >>> within the confines of the red chair. Perhaps it is more a case of
> >>> specialization than alternateOf in this case.  (and so a strong
case
> >>> for why specializationOf is not a subproperty of alternateOf)
> >>>
> >>> But this thing with the atoms is not true. A customer is not a set
of
> >>> atoms. A cafe *customer* is a concept which depends on the
> >>> interactions with the cafe. While Paolo was in the cafe, he sat in
the
> >>> red chair and ordered coffee - and so for a period (the full
lifetime
> >>> of paoloInCafe) he also became customerOnRedChair.
> >>>
> >>>
> >>> This would probably be fine then:
> >>>
> >>> specializationOf(paoloInCafe, customerOnRedChair)
> >>> specializationOf(paoloInCafe, paolo)
> >>>
> >>> -->
> >>> alternateOf(paolo, customerOnRedChair)
> >>>
> >>> which makes sense - they are both talking about the same thing.
> >>>
> >>>
> >>>
> >>> but if we also have the equivalent assertions about Stian - but
the
> >>> old characterisation interval of paoloInCafe never overlaps that
of
> >>> stianInCafe - then I feel they should *not* be alternateOf each
other,
> >>> because they did not exist at the same time.
> >>>
> >>> So similarly I would not like to conclude alternateOf(Bush, Obama)
> >>>
> >>> .. because if we do, then as far as I can tell there is not much
value
> >>> in alternateOf() any more.
> >>>
> >>>
> >>>
> >>> And that is perhaps my point. We can't have a single hierarchical
> >>> structure organizing everything that exists (and talk about "the
same
> >>> real world thing"), because we include in "exists" various
abstract
> >>> concepts and simplifications that are not easily mappable to our
> >>> understanding of the physical world.
> >>>
> >>> I am sure we can agree that this email message can be
characterised by
> >>> an entity. However you can't easily map that entity to electrons
on
> >>> the wire or photons coming out of the screen - although we are of
> >>> course aware that the message would not exists without those.
> >>>
> >>>
> 
> 
> --
> -----------  ~oo~  --------------
> Paolo Missier - Paolo.Missier@newcastle.ac.uk, pmissier@acm.org
> School of Computing Science, Newcastle University,  UK
> http://www.cs.ncl.ac.uk/people/Paolo.Missier
> 
> 
> 
>
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Received on Thursday, 19 January 2012 11:21:15 UTC

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