proposed response to public comment (deadline Tuesday noon GMT)

Dear all,

At 
http://www.w3.org/2011/prov/wiki/ResponsesToPublicComments#PROV-DM_.28Under_Review.29 

you will find proposed answers to the ISSUE-475. It is copied below for 
your convenience.

It will become the group response unless we hear objections by Tuesday 
November 6th, noon GMT.

Best regards,
Luc


      ISSUE-475 (Mention)

  * Original
    email:http://lists.w3.org/Archives/Public/public-prov-comments/2012Aug/0001.html
  * Tracker:http://www.w3.org/2011/prov/track/issues/475
  * Group Response:
      o The reviewer suggests that the work to describe contextualized
        provenance should be deferred so that it can be aligned with
        ongoing W3C work on RDF datasets and their semantics. Since
        ISSUE-475 was submitted, the RDF working group has decided that
        it will not provide a formal semantics for RDF Datasets. This
        RDF resolution ensures that any semantics for bundle and/or
        mention is guaranteed not to be in conflict with the RDF semantics.
      o As PROV-Constraints section 6.2 clearly indicates, PROV-bundles
        validity is determined by examining bundles in isolation of each
        other. Our response to issue-482 also indicates that PROV itself
        does not set any constraints on how a given ID is being used
        across multiple bundles. Given this,/mentionOf is a general
        relation which allows an entity to be linked to another entity
        described in another bundle/.
      o The reviewer suggests that

    mentionOf(infra, supra, b)

could simply be expressed as

   specializationOf(infra, supra)
   entity(infra, [mentionedIn=b])

  *
      o This design was considered and rejected by the Working Group:
          + By design, relations between PROV objects are expressed by
            PROV relations (usage, generation, etc, mention), and are
            not expressed as PROV attributes. The suggested additional
            attribute mentionedIn would relate the entity infra with
            bundle b, and would go against this prov-dm design.
          + The interpretation of the attribute-value pair mentionedIn=b
            is somewhat difficult, because infra is not itself described
            in bundle b: supra is the entity described in bundle b. So,
            syntactically, mentionedIn=b may look like an
            attribute-value pair, but in reality, it can only be
            understood in the presence of specializationOf(infra,
            supra). Hence, the reason for introducing the ternary
            relation mentionOf.
      o The Working Group left it unspecified which new attributes could
        be inferred for infra, and in general what constraints apply to
        mentionOf. The reviewer is critical of this decision, arguing
        that nothing new can be inferred from mentionOf, and therefore
        mentionOf can be replaced by specializationOf.
        'Under-specification' is a feature of PROV: what can be inferred
        from relations such as usage, derivation, alternate? The group
        recently acknowledged this for alternateOf and added a
        clarifiying note in the text. This observation is applicable to
        further PROV concepts, such as Quotation, PrimarySource,
        SoftwareAgent, etc. which do not allow us to infer more than
        their parent concept would (Derivation, Agent). We are in a same
        situation with mentionOf. Further inferences are left to be
        specified by applications.
      o The reviewer's suggestion to address the use of Example 45 is to
        copy part of the referred bundle. By/copying/statements from the
        original context to the new context, we have lost the original
        context in which they occur (... their provenance!), and we have
        no way of expressing that wasAssociatedWith(ex:a1, ...) in the
        new context is a "kind of specialization" of
        wasAssociatedWith(ex:a1,...) in the original context, ... which
        is why mentionOf was introduced in the first place.
      o The reviewer also comments on the lack of information about
        'Fixed aspects'. We refer to our response to ISSUE-462, and
        recent associated changes to the document.
      o The Working Group identified 'mention' as a feature at risk,
        because it was seeking experience from implementers. The Working
        Group will keep this feature marked at risk as it enters the CR
        phase, and will reassess its suitability based on implementers
        feedback.
  * References:
      o RDF
        resolution:http://www.w3.org/2011/rdf-wg/meeting/2012-10-03#resolution_1
      o Email discussion on
        mention:http://lists.w3.org/Archives/Public/public-prov-wg/2012Jun/0400.html
      o alternateOf:http://dvcs.w3.org/hg/prov/diff/60b6ee097555/model/prov-dm.html#l1.8
      o Response to
        ISSUE-482:http://www.w3.org/2011/prov/wiki/ResponsesToPublicComments#ISSUE-482_.28Bundles_and_IDs.29
      o Prov constraints section
        6.2:http://www.w3.org/TR/prov-constraints/#bundle-constraints
      o Response to
        ISSUE-462:http://www.w3.org/2011/prov/wiki/ResponsesToPublicComments#ISSUE-462_.28Definition_of_Entity.29
  * Changes to the document:
  * Original author's acknowledgement:


    [edit
    <http://www.w3.org/2011/prov/wiki/index.php?title=ResponsesToPublicComments&action=edit&section=46>]



-- 
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 Kingdom                     http://www.ecs.soton.ac.uk/~lavm