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Re: Some thoughts about the revised provenance Model document

From: Stian Soiland-Reyes <soiland-reyes@cs.manchester.ac.uk>
Date: Thu, 20 Oct 2011 13:55:17 +0100
Message-ID: <CAPRnXtk_8ALntv9rC7banowkgrCa02PsyRWEMH-nKdodpdTaSw@mail.gmail.com>
To: Paul Groth <p.t.groth@vu.nl>
Cc: Graham Klyne <Graham.Klyne@zoo.ox.ac.uk>, "Myers, Jim" <MYERSJ4@rpi.edu>, W3C provenance WG <public-prov-wg@w3.org>, "Luc Moreau (L.Moreau@ecs.soton.ac.uk)" <L.Moreau@ecs.soton.ac.uk>
On Thu, Oct 20, 2011 at 10:37, Paul Groth <p.t.groth@vu.nl> wrote:

> cf:e2 a prov:Entity.
> cf:e2 cf:hasLocation dbpedia:Berlin.
> dbpedia:Berlin dbpedia-owl:leader dbpedia:Klaus_Wowereit.
> dbpedia:Klaus_Wowereit dbpprop:nationality dbpedia:Germany.
>
> Obviously, I can just keep building this massive graph using linked data.
> If that's the case what characterizes cf:e2?
> Is it just cf:hasLocation dbpedia:Berlin or is it everything else?

IMO:

Only
   cf:e2 cf:hasLocation dbpedia:Berlin .

would be characterizing cf:e2.


dbpedia:Berlin is not characterized - unless it was also a prov:Entity.


Now I don't know the answer for anonymous nodes:

cf:e2 a prov:Entity.
cf:e2 cf:hasLocation [
   dbpedia-owl:leader [
      foaf:name "Klaus Wowereit"
      dbpprop:nationality dbpedia:Germany
    ],
]


My simple reading of this is that cf:e2 has a location of somewhere
where the German called Klaus Wowereit is "the leader" - but neither
Hr B├╝rgermeister Wowereit or the implied Berlin is a "characterising
attribute".

If we distance ourselves slightly from the notions of "characterising
attributes" we can just say that the properties stated directly on (or
with?) an entity was true/fixed attributes throughout the lifetime of
the entity. Any nested propertioes might or might not have been true/
throughout that lifetime.  (Thus cf:e2 could have existed in Berlin
before Hr Wowereit became the mayor).


I suggest that if you also want to lock down such things, then do
those properties as other prov:Entities, (either anonymous or named):

cf:e2 a prov:Entity ;
  cf:hasLocation cf:berlinWithKlaus .

cf:berlinWithKlaus a prov:Entity, prov:Location ;
  prov:wasComplementOf  dbpedia:Berlin ;
  dbpedia-owl:leader cf:klausTheMayor .

cf:klausTheMayor a prov:Entity ;
    prov:wasComplementOf dbpedia:Klaus_Wowereit ;
    dbpedia:Klaus_Wowereit dbpprop:nationality dbpedia:Germany .


Thus throughout the lifetime of cf:e2, the thing described by e2 was
in Berlin, and throughout that time (at least as long as e2 existed)
Klaus Wowereit was the leader, being German (The pre-1990
Klaus-the-West-German was not the leader during the lifetime of
cf:berlinWithKlaus).


Note that such an interpretation would introduce temporal dependencies
between cf:e2 and cf:klausTheMayor which are not currently covered by
PROV-DM (there are no prov:derivedFrom or wasComplementOf links
between cf:e2 and Berlin) - if the provenance otherwise showed that
Klaus became mayor (when cf:klausTheMayor was generated) *afte*r cf:e2
was generated, then the provenance account is inconsistent,  but this
can't be shown by the constraints of PROV-DM as far as I can tell.



Note that PROV-DM does not specifically allow such nesting of
attribute values, there all attribute values are strings. If a
property value was to be interpreted as a URI or identifier of another
entity or other resource, than that seems outside of scope for PROV-DM
- so we can take the same view in PROV-O.


-- 
Stian Soiland-Reyes, myGrid team
School of Computer Science
The University of Manchester
Received on Thursday, 20 October 2011 12:56:16 GMT

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