W3C home > Mailing lists > Public > public-prov-wg@w3.org > July 2011

PROV-ISSUE-56 (derivation-definition-does-not-imply-transitivity): Derivation as defined is not transitive [Conceptual Model]

From: Provenance Working Group Issue Tracker <sysbot+tracker@w3.org>
Date: Fri, 29 Jul 2011 09:01:11 +0000
To: public-prov-wg@w3.org
Message-Id: <E1QmiwR-0000WC-T3@stu.w3.org>

PROV-ISSUE-56 (derivation-definition-does-not-imply-transitivity): Derivation as defined is not transitive [Conceptual Model]

http://www.w3.org/2011/prov/track/issues/56

Raised by: Graham Klyne
On product: Conceptual Model


[[ Given an assertion isDerivedFrom(B,A), one can infer that the use
of characterized entity denoted by A precedes the generation of the
characterized entity denoted by B.  ]] 
Where does this notion of "use" come from in the absence of some
referenced activity?

Concerning transitivity of derivation:

Suppose:
A has attributes a0, a1
B having attributes b0, b1 is derived from A, with b0 being dependent on a0
C having attributes c0, c1, is derived from B with c1 being dependent on b1

So none of the attributes of C can be said to be directly or
indirectly dependent on attributes of A, which by the given definition
is a requirement for derivation of C from A.  Thus, as defined,
derivation cannot be transitive.

I don't really know if derivation should or should not be transitive,
but the above seems to me like a problem of spurious
over-specification.  My suggestion for now would be to focus on what
really matters and see what logical properties fall out later.
Received on Friday, 29 July 2011 09:01:16 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Thursday, 26 April 2012 13:06:37 GMT