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prov-dm attributes: two proposals to vote on (deadline Wednesday midnight GMT)

From: Luc Moreau <l.moreau@ecs.soton.ac.uk>
Date: Sun, 30 Oct 2011 17:54:37 +0000
Message-ID: <EMEW3|ead62e083afa7897a78b86b6e6853e54n9YHse08l.moreau|ecs.soton.ac.uk|4EAD8F5D.8080009@ecs.soton.ac.uk>
To: W3C provenance WG <public-prov-wg@w3.org>




In the interest of simplification, we would like to make the following
proposal about attributes in prov-dm.

Proposal 1: attributes are a necessary part of prov-dm. Attribute-value 
pairs can be optionally
   included in Entity Expressions and Activity Expressions.

The document will justify their presence along the following lines
(text to be worked on, suggestions welcome). For inter-operability
purpose, it is necessary to be able to describe entities (and
activities), and such descriptions need to be part of the provenance
record, so that queries over such descriptions can be expressed.  The
document will not make the distinction between non-characterizing and
characterizing attributes. All attributes will be considered as
describing some facet of the entity.

Proposal 2: Constraints related to attributes will be dropped.
http://www.w3.org/TR/2011/WD-prov-dm-20111018/#derivation-attributes
http://www.w3.org/TR/2011/WD-prov-dm-20111018/#use-attributes
http://www.w3.org/TR/2011/WD-prov-dm-20111018/#generation-affects-attributes

Rationale: a number of issues have been raised against these
constraints. They may or may be fixable. But overall, they seem to
overconstraint the model, for benefits that are unclear.  There was no
intent to make them automatically verifiable, for
instance. Furthermore, if it is really crucial for some developers to
express that some attributes depend on others, than prov-dm already
offers a mechanism: simply model these attributes as entities, and their
dependency as derivation.

A further consequence is that derivation can be made transitive!
(subject of a separate proposal)

Finally, the semantics team may want to reconsider these constraints and 
formalize them properly.

Cheers,
Luc
Received on Sunday, 30 October 2011 17:56:24 GMT

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