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Re: PROV-ISSUE-153 (complementarity): Complementarity description differs from model definition [Primer]

From: Simon Miles <simon.miles@kcl.ac.uk>
Date: Thu, 1 Dec 2011 15:49:52 +0000
Message-ID: <CAKc1nHeBqCLGW6RAi_GJHzpt_Qitr_s7xumOMqkC24nbHnSgSw@mail.gmail.com>
To: Provenance Working Group WG <public-prov-wg@w3.org>
Hello all,

I have tried to correct the complementarity intuition text in the
primer while staying brief and untechnical.

Please could you see whether it makes sense to you and resolves the
issue (esp. Stian and Graham)?

http://dvcs.w3.org/hg/prov/raw-file/default/primer/Primer.html#complementarity

The suggestion of separating complementarity and 'restriction' might
be helpful for explanation, if not interoperability. I think it is
difficult to include both a symmetric and an asymmetric relation in a
single concept with a single name.

Thanks,
Simon


On 23 November 2011 16:34, Graham Klyne <GK@ninebynine.org> wrote:
> Hi Paolo, comment below...
>
> On 23/11/2011 09:56, Paolo Missier wrote:
>>> Out of interest, do you have a use-case for which complementarity depends on
>>> there being an actual overlap of attributes, as opposed to both being
>>> contextualizations of some common thing?
>
>> the old "royal society" example is meant to exemplify a pattern where each
>> observer has a partial view on some system state (state = complete set of
>> attribute value pairs), but there is no "common thing" that is given to them:
>> nobody has the /complete/ state. Indeed, the idea is that the common thing
>> emerges by taking the union of the two sets of attributes, on the basis that the
>> overlapping portions are mutually consistent (i.e. a mapping can be established).
>> We may be saying the same thing: a "common thing" that subsumes both exists, but
>> in this example it only becomes manifested /as a consequence of/ the observers
>> agreeing that they are each looking at two projections of it.
>>
>> Indeed your last comment seems to agree with this view: in an open world, there
>> is some common entity that subsumes our views, but it may not have been explicated.
>>
>> The inspiration for this is the notion of "record linkage", or the process by
>> which you "discover" such common entity, and you benefit from the discovery by
>> taking all that you know from each of the individual pieces. I just would like
>> to have this setting expressed as part of PROV because it's the only place where
>> you can make an attempt at "joining up" or reconcile different assertions made
>> independently about what is in reality the "common thing".
>>
>> I think what you are referring is complementary to this, namely you do have a a
>> priori "common thing", you derive views from it, and you call them the
>> complement of each other.
>
> Yes, complementary (sic) indeed.
>
> Maybe I'm missing something here, but absent knowledge of the existence of some
> a priori common thing (whether or not one knows what that thing is), it seems to
> me that there's very little one can reliably infer from some common attribute.
> Consider:
>
>   Entity( e1, [membership=50] )
>
>   Entity( e2, [membership=50] )
>
> If it happens that e1 is a contextualization of "Royal Society", and e2 is a
> contextualization of the "Historical Society", I think the common attribute here
> tells us nothing of import regarding provenance.
>
> (I should re-check PROV-DM on this, but I'm out of time right now.)
>
> #g
> --
>
>> I see no conflicts here, I believe that both should be expressible.
>>
>> Regarding terminology, either "restriction" or "projection" work relative to the
>> common thing, but they don't work in relation to each other. In any case, both
>> are meant in their algebraic sense:
>>
>> restriction: "Any function can be restricted to asubset
>> <http://en.wikipedia.org/wiki/Subset>of its domain. The restriction of/g/ : /A/
>> ? /B/to/S/, where/S/?/A/, is written/g/ |_/S/ : /S/? /B/."
>> (http://en.wikipedia.org/wiki/Function_restriction)
>>
>> projection: well, this we all know :-)
>>
>> --Paolo
>>
>>
>>>
>>> (Arguably, in an open-world environment such as the web, the fact that two
>>> entities contextualize some common other entity suggests very strongly that
>>> there does exist some attribute that is common, even if it has not been
>>> explicated.)
>>>
>>> #g
>>> --
>>
>>
>
>



-- 
Dr Simon Miles
Lecturer, Department of Informatics
Kings College London, WC2R 2LS, UK
+44 (0)20 7848 1166

Modelling the Provenance of Data in Autonomous Systems:
http://eprints.dcs.kcl.ac.uk/1264/
Received on Thursday, 1 December 2011 15:50:31 UTC

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