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PROV-ISSUE-122: Constraint on wasGeneratedBy (PROV-DM and PROV-OM) [Conceptual Model]

From: Provenance Working Group Issue Tracker <sysbot+tracker@w3.org>
Date: Sun, 09 Oct 2011 23:36:11 +0000
To: public-prov-wg@w3.org
Message-Id: <E1RD2uh-0000Wq-Rn@lowblow.w3.org>

PROV-ISSUE-122: Constraint on wasGeneratedBy (PROV-DM and PROV-OM)  [Conceptual Model]

http://www.w3.org/2011/prov/track/issues/122

Raised by: Satya Sahoo
On product: Conceptual Model

The following constraint is defined on wasGeneratedBy in the PROV-DM document (as on Oct 9, 2011):
"Given a process execution pe, entity e, role r, and optional time t, if the assertion wasGeneratedBy(e,pe,r) or wasGeneratedBy(e,pe,r,t) holds, the values of some of e's attributes are determined by the activity denoted by pe and the entities used by pe. Only some (possibly none) of the attributes values may be determined since, in an open world, not all used entities may have been asserted."

Issue: This constraint seems to be self-contradictory due to the two phrases "...the values of some of e's attributes are determined by the activity denoted by pe..." and "Only some (possibly none) of the attributes values may be determined...". 

In addition, this constraint cannot be enforced, since which attributes will be determined are not specified and given the use of open world assumption, there be always some attribute that is not currently associated with the entity.

Overall, this constraint does not help either in inferring new knowledge from existing information or allow "validation/checking" of existing knowledge - which are the standard uses of rules/constraints. Hence, the suggestion is to remove this constraint.
Received on Sunday, 9 October 2011 23:36:13 GMT

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