- From: Graham Klyne <GK@ninebynine.org>
- Date: Thu, 04 Aug 2011 08:22:22 +0100
- To: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
- CC: public-prov-wg@w3.org
Short answer: no. Longer answer: I think we should focus on describing what needs to be described, and allow the inferences to follow (or not) from that. I think to construct definitions to achieve desired inferences is putting the cart before the horse. Further, I think that there's a real danger that by focusing on inferences rather than descriptions, we end up with terms whose descriptive role is counter-intuitive, and which will, in the end, be used or generated incorrectly by systems on the deployed web. IMO, it's easier to add constraints later to enable inferences than it is to work around unwanted constraints that are baked into a vocabulary. Particularly on an open-world monotonic logic language like RDF (which I assume will provide the base language for actually implementing these descriptions). #g -- Luc Moreau wrote: > Hi all, > > Nice counter-example, Graham! > > We have the opportunity to define relationships with the properties we > want them to have. > > Do we want (a form of ) derivation to be transitive? > > In the example that Graham provides, do you feel that A has some form of > "influence" on C? > If so, would you like it to be automatically inferable in the provenance > model? > > Regards, > Luc > > > On 07/29/2011 10:01 AM, Provenance Working Group Issue Tracker wrote: >> 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 Thursday, 4 August 2011 08:41:56 UTC