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Precision of qualified involvements

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luc 7 Nov 2011 (off list):

6. It would be good to write that unqualified involvement is "unprecise".
   When we assert used(pe,e),
   it could be because of QualifiedUse(pe,e,t1,role=r1)  and QualifiedUse(pe,e,t2,role=r2).
   So, used(pe,e) gives a *lower bound* on the number of actual uses.


+ http://www.w3.org/mid/EMEW3%7Cc56773d6a135f16a79087df7872e3f7cnAFEpY08L.Moreau%7Cecs.soton.ac.uk%7C4EC3CDED.1090101@ecs.soton.ac.uk

In light of this discussion, I feel we could come to the following proposals.

1.  Subsection on derivation would define two relations only.
  wasDerivedFrom: linked to 1 activity only
  wasBasedOn (used to be called wasEventuallyDerivedFrom):  linked to unspecified number of activities

   wasDerivedFrom is a special case of wasBasedOn in the following sense:
   wasDerivedFrom(e2,e1) implies wasBasedOn(e2,e1)


   Both wasDerivedFrom and wasBasedOn are non-transitive.
   Indeed, we can find examples where transitivity does not make sense.

2. A new section introducing a transitive relation
   computed as a transitive closure over:
       wasControlledBy
       wasComplementOf
       wasBasedOn
   Not sure what its names, but should capture the idea of being in the history of the subject.

What do you think?

Simon, wasBasedOn/wasEventuallyDerivedFrom: is it right to say that the only difference between
wasBasedOn and wasDerivedFrom is that the latter is associated to one and only one activity, while
the former may be associate to many (and their number may be unknown).

Luc

Yes, as you say, I think the only difference between wasDerivedFrom
and wasBasedOn is that the former is used where you wish to express
what activity the derivation was due to, while the latter implies
nothing about activities (and so may be due to many).