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

From: Khalid Belhajjame <Khalid.Belhajjame@cs.man.ac.uk>
Date: Thu, 29 Sep 2011 16:02:20 +0100
Message-ID: <4E84887C.1000005@cs.man.ac.uk>
To: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
CC: public-prov-wg@w3.org
On 29/09/2011 15:55, Luc Moreau wrote:
> Or can it be on entities? We could offer the option to express the 
> characterization interval in the entity expression.

Yes, I would go for this option, we can call it validity interval.

Khalid

>
> Luc
>
> On 09/29/2011 03:52 PM, Myers, Jim wrote:
>>
>> So the missing functionality is time constraints on the duration of 
>> the complementOf relation? Or is something else/additional needed?
>>
>> Jim
>>
>> *From:*public-prov-wg-request@w3.org 
>> [mailto:public-prov-wg-request@w3.org] *On Behalf Of *Cresswell, Stephen
>> *Sent:* Thursday, September 29, 2011 10:16 AM
>> *To:* public-prov-wg@w3.org
>> *Subject:* RE: PROV-ISSUE-29 (mutual-iVP-of): can two bobs be 
>> mutually "IVP of" each other [Conceptual Model]
>>
>> Hi Jim,
>>
>> Thanks for your comments.  Sorry for the delay in responding -- 
>> please see responses inline below.
>>
>> Stephen Cresswell
>>
>> ------------------------------------------------------------------------
>>
>> *From:*Myers, Jim [mailto:MYERSJ4@rpi.edu]
>> *Sent:* 26 September 2011 16:35
>> *To:* Cresswell, Stephen; Paolo Missier; public-prov-wg@w3.org
>> *Subject:* RE: PROV-ISSUE-29 (mutual-iVP-of): can two bobs be 
>> mutually "IVP of" each other [Conceptual Model]
>>
>> Jim Myers wrote:
>> > I'm not sure what of 29 and 57 then survive as unresolved concerns - 
>> perhaps whether transitivity can be defined?
>>
>> I have two concerns (or perhaps the same concern approached from two 
>> directions).
>>
>> (1)
>> I think that the assertion wasComplementOf(B,A) implicitly defines a 
>> new entity.
>> The new entity has a time interval which is the temporal intersection 
>> of those of A and B.
>> The new entity has a set of attribute-value pairs which is the union 
>> of those of A and B.
>>
>> However, if I want to make this new entity explicit, I can't.  The 
>> vocabulary I need to use to state its relationship to A and B is missing.
>>
>> ---- Why not C with attributes location and membership that is a 
>> complement of A and B?
>>
>> If we have the assertions: wasComplementOf(B,A), wasComplement(C,A), 
>> wasComplement(C,B), we still haven't expressed that the time interval 
>> of C is within those of both A and B.  Because we couldn't express 
>> that, we couldn't infer C's attributes, although of course we can 
>> assert them.
>>
>>
>> (2)
>> One use for the original IVPof was (I thought) to relate together 
>> long-term entities (e.g. Luc-over-his-lifetime) with shorter-term 
>> entities describing states (e.g. Luc-in-Boston).  Now it seems that 
>> the strongest assertion that I can make about the relationship of 
>> these two entities is:
>>
>>   wasComplementOf( Luc-in-Boston, Luc-over-his-lifetime )
>>
>> ... but this just asserts that Luc's visit to Boston *overlapped* 
>> with his lifetime, which is weaker than what I wanted to assert.
>>
>> --what's missing? I take this as meaning there was a Luc-in-Boston 
>> entity that is an alternate characterization of Luc that is only 
>> valid during his trip to Boston, not that these entities just coexist 
>> in time. Do you want something more than that or do you think that 
>> interpretation is not captured in the definition of complementOf?
>>
>> I want to express that Luc-in-Boston was entirely within 
>> Luc-over-his-lifetime, and therefore everything invariant in 
>> Luc-over-his-lifetime is also invariant for the whole duration of 
>> Luc-in-Boston.  Also, I want to make the transitive inference of the 
>> same relationship between Luc-at-MIT and Luc-over-his-lifetime.
>>
>>
>> If I also want to describe a visit to MIT that Luc made while in 
>> Boston, I could also assert
>>
>>   wasComplementOf( Luc-at-MIT, Luc-in-Boston )
>>
>> Since the assertions are quite vague, we can't infer that 
>> Luc-over-his-lifetime contained Luc-at-MIT, and we can't even infer 
>> that they overlapped.
>> I think it would be useful to be able to make some stronger 
>> assertions that allow transitivity to be used here.  At some point 
>> during its evolution, IVPof was close to being that helpful 
>> transitive relation, but now its gone.  I think we still need it.
>>
>> --- What's missing from the complementOf definition (that was in 
>> ivpOf?)? Doesn't your assumption above that there's a new entity that 
>> is the intersection of two complementary entities force transitivity 
>> during the intersection interval?
>>
>> I don't see how to express that using wasComplementOf.
>>
>>
>> Stephen Cresswell
>>
>> -----Original Message-----
>> From: Myers, Jim [mailto:MYERSJ4@rpi.edu]
>> Sent: Fri 23/09/2011 18:21
>> To: Cresswell, Stephen; Paolo Missier; public-prov-wg@w3.org
>> Subject: RE: PROV-ISSUE-29 (mutual-iVP-of): can two bobs be mutually 
>> "IVP  of"  each other  [Conceptual Model]
>>
>> When I read the current document, I see complementOF is defined as 
>> one-way - you can assert it in both directions, but the text talks 
>> about a case where B is a complementOf A but not the reverse. Can the 
>> editors confirm that's the intent? If so, perhaps we can move to 
>> refining text to avoid the perception that symmetry is required (i.e. 
>> talk about the asymmetric case first...). I'm not sure what of 29 and 
>> 57 then survive as unresolved concerns - perhaps whether transitivity 
>> can be defined?
>>
>> Cheers,
>>  Jim
>>
>> > -----Original Message-----
>> > From: public-prov-wg-request@w3.org 
>> <mailto:public-prov-wg-request@w3.org> [mailto:public-prov-wg-
>> > request@w3.org <mailto:request@w3.org>] On Behalf Of Cresswell, Stephen
>> > Sent: Friday, September 23, 2011 10:15 AM
>> > To: Paolo Missier; public-prov-wg@w3.org <mailto:public-prov-wg@w3.org>
>> > Subject: RE: PROV-ISSUE-29 (mutual-iVP-of): can two bobs be mutually 
>> "IVP
>> > of" each other [Conceptual Model]
>> >
>> >
>> > Hi Paolo,
>> >
>> > Yes, I agree that the current wasComplementOf can be symmetrical, and I
>> > have no objection to closing issue 29.
>> >
>> > I do still think that a concept of IVPof that is antisymmetric and 
>> transitive, so
>> > that "B IVPof A" means something like "B and A describe the same stuff,
>> > and B's interval is within A's interval" is a simpler and stronger 
>> concept.  It
>> > can co-exist with wasComplementOf, and it can be used to define (a
>> > symmetric form of) wasComplementOf (which admittedly doesn't match
>> > the current definition).
>> > i.e.
>> >   (B wasComplementOf A) <=> exists C.(C IVPof A & C IVPof B)
>> >
>> > Since wasComplementOf is a relation that only holds over the temporal
>> > intersection A and B anyway, then saying it with this IVPof at least 
>> makes
>> > you introduce an entity C that models the relevant interval.
>> >
>> > However, I think that's basically what Graham said and it is a 
>> different issue
>> > - PROV-ISSUE-57.
>> >
>> > Stephen Cresswell
>> >
>> > Tel:  +44 (0) 01603 69 6926
>> >
>> > Web: www.tso.co.uk <http://www.tso.co.uk>
>> >
>> >
>> >
>> >
>> > -----Original Message-----
>> > From: public-prov-wg-request@w3.org 
>> <mailto:public-prov-wg-request@w3.org>
>> > [mailto:public-prov-wg-request@w3.org] On Behalf Of Paolo Missier
>> > Sent: 23 September 2011 12:06
>> > To: public-prov-wg@w3.org <mailto:public-prov-wg@w3.org>
>> > Subject: Re: PROV-ISSUE-29 (mutual-iVP-of): can two bobs be mutually 
>> "IVP
>> > of" each other [Conceptual Model]
>> >
>> > Hi,
>> >
>> > as we are going through older issues, this one seems to have been
>> > superseded by the current version of the model. We propose to close it
>> > pending review (that means, Stephen can you please call in with your
>> > current view on this, thank you).
>> >
>> > Specifically:  IVP-of has been replaced by ComplementOf, which *does*
>> > allow for symmetry.
>> >
>> > -Paolo
>> >
>> >
>> > On 7/11/11 12:22 PM, Provenance Working Group Issue Tracker wrote:
>> > > PROV-ISSUE-29 (mutual-iVP-of): can two bobs be mutually "IVP of" each
>> > other  [Conceptual Model]
>> > >
>> > > http://www.w3.org/2011/prov/track/issues/29
>> > >
>> > > Raised by: Stephen Cresswell
>> > > On product: Conceptual Model
>> > >
>> > >
>> > > As it currently stands, I believe that it does not exclude the
>> > possibility that two bobs may be mutually "IVP of" each other -
>> > > i.e. you could have bobs A, B such that (B IVPof A)&  (A IVPof B), and
>> > this is surely not intended.
>> > >
>> > > This could arise if, for bobs A, B :
>> > > - A and B both represent the same entity
>> > > - A and B share some immutable properties, and they have corresponding
>> > values.
>> > > - B has some immutable properties which correspond to mutable
>> > properties of A
>> > > - A has some immutable properties which correspond to mutable
>> > properties of B
>> > >
>> > > Possibly the asserter-defined test (included in "IPV of" definition)
>> > that real world states modelled by A and B are "consistent" may disallow
>> > > "IPV of" in this situation.  However, unless that is guaranteed, I
>> > think that the definition of "B IPV of A" (if it is still to have a
>> > definition) should additionally require that:
>> > > "A has no immutable properties which correspond to mutable properties
>> > of B"
>> > >
>> > > Stephen
>> > >
>> > >
>> > >
>> > >
>> >
>> >
>> > --
>> > -----------  ~oo~  --------------
>> > Paolo Missier - Paolo.Missier@newcastle.ac.uk 
>> <mailto:Paolo.Missier@newcastle.ac.uk>, pmissier@acm.org 
>> <mailto:pmissier@acm.org> School
>> > of Computing Science, Newcastle University,  UK
>> > http://www.cs.ncl.ac.uk/people/Paolo.Missier
>> >
>> >
>> >
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>
> -- 
> 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 Kingdomhttp://www.ecs.soton.ac.uk/~lavm
Received on Thursday, 29 September 2011 15:02:48 GMT

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