- From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
- Date: Mon, 7 Nov 2011 19:34:29 +0000
- To: Simon Miles <simon.miles@kcl.ac.uk>
- CC: Provenance Working Group WG <public-prov-wg@w3.org>
Hi Simon, We didn't have transitivity on derivation because of the constraint on attributes but it was dropped last week. If you think that we need a non-transitive relation wasEventuallyDerivedFrom, can you explain why? Why do you come back on something you had agreed upon? If you don't make the link to the PE, how can you decide which PE underpinned the derivation? To me, when generating provenance in a computational context, eg workflow, it's the only derivation that is grounded and can be verified. Professor Luc Moreau Electronics and Computer Science University of Southampton Southampton SO17 1BJ United Kingdom On 7 Nov 2011, at 17:57, "Simon Miles" <simon.miles@kcl.ac.uk> wrote: > Hello Luc, > > +1 for Proposal 1; 0 for Proposal 2; -1 for Proposal 3 > > Proposal 1 sounds fine, but in what way do Proposals 1 and 2 differ > from what exists at the moment? > > More importantly, I can't see anything in the text about > wasEventuallyDerivedFrom being transitive, or see why it would be, so > why does Proposal 3 make sense? > > With the two separate links, we are able to assert and query for an > actual connection between one entity's content and another's > (wasEventuallyDerivedFrom), while also allowing the entities involved > somewhere in an entity's history to be browsed (dependedUpon). This > seems to allow for two clear classes of use case for two common > interpretations of provenance. > > The one I still don't see the value of is wasDerivedFrom. If you can > say that A wasEventuallyDerivedFrom B, that P used B and P generated > A, then what more is there to say? If wasDerivedFrom is just a > shortcut for this information, why is it significant enough to warrant > being added to the model? Why would you assert an account where you > can say A wasDerivedFrom B, because you know about P, but you do not > say P used B and P generated A? > >> From our earlier discussions, I understand the distinction of > derivation types, but wasDerivedFrom just seems a less useful and more > complex to understand version of wasEventuallyDerivedFrom. > > Thanks, > Simon > > On 7 November 2011 10:06, Luc Moreau <l.moreau@ecs.soton.ac.uk> wrote: >> Dear all, >> >> Can you express your support or not for the following proposals. We will >> confirm >> the outcome at the teleconference. >> >> Best regards, >> Luc >> >> >> In the interest of simplification, we would like to make the following >> proposal about derivations in prov-dm. >> >> Context: prov-dm currently contains 3 different notions of >> derivations, in particular with names that are not intuitive. The >> constraint derivation-attributes [1] prevented derivations to be >> transitive. These constraints were removed from the prov-dm document >> last week [2]. >> >> >> >> Proposal 1. Transitive derivation is expressed using 'dependedUpon' >> between two entities. dependedUpon can be asserted or >> inferred. >> >> Proposal 2. There exists a special case of derivation, where a >> process execution is known or known to exist. This is >> expressed using: >> wasDerivedFrom(e2,e1,[pe, ...]) and its compact form >> wasDerivedFrom(e2,e1). >> >> Furthermore, there exists an inference: >> wasDerivedFrom(e2,e1,[pe, ...]) implies dependedUpon(e2,e1). >> >> Proposal 3. In the current version of the document, >> wasEventuallyDerivedFrom and dependedOn intended to >> express the same notion of (transitive) derivation, and >> thus can be >> removed as redundant. >> >> >> >> Instead of 3 relations wasDerivedFrom, wasEventuallyDerivedFrom, and >> dependedOn, we would now only have 2 relations wasDerivedFrom and >> dependedUpon. The awkward term 'wasEventuallyDerivedFrom' is also >> abandonned. Overall, this should contribute towards a simplification >> of the model. >> >> >> Note: the text will describe the conditions under which the binary >> form of wasDerivedFrom is transitive. >> >> >> >> >> [1] http://www.w3.org/TR/2011/WD-prov-dm-20111018/#derivation-attributes >> [2] http://www.w3.org/2011/prov/meeting/2011-11-03#resolution_5 >> >> >> > > > > -- > Dr Simon Miles > Lecturer, Department of Informatics > Kings College London, WC2R 2LS, UK > +44 (0)20 7848 1166 >
Received on Monday, 7 November 2011 19:35:19 UTC