PR#2 for Provenance DM : syncronicity with vocabularies definition in Semantics WG

[Markus Demleitner]

Hi DM,

On Wed, Sep 04, 2019 at 12:43:56PM +0200, Mireille LOUYS wrote:
> Thanks for reading the document and providing your comments.
> 
> Concerning the definition of a vocabulary for some attributes of the
> Provenance model, like Agent Role literals,
> 
> I think the DM specification should not rely on the current elaboration of
> the vocabulary definition proposed by the Semantics WG.

The problem is that it's hard to put in anything normative later,
because if there's anything like a "must" (as in VO-DML
semanticConcept), you'd be invalidating existing instances -- and so
you'd need a new major version of ProvDM.

You could probably move enums to vocabularies (this would be relaxing
constraints, which might still break clients, though).  However, the
enums would have to be defined, and I don't think anyone would want
to do that.

Finally, you could put in "should"s.  But until then you'll have
natural language in the fields, and that will make it very hard to
interoperably do much interesting with them.

> For now, these literals should be part of the PROV-DM specification , and
> when we have feedback from implementations ,
> we will be able to understand the needs for evolution for these lists of
> terms better, and propose an IVOA provenance vocabulary.

Well, this is exactly what we have vocabularies for:  Start with a
minimal set, add terms as necessary.

> By adding too many constraints on this specification , we will delay it
> again, and it is not what we wish for the IVOA.

Given that there are no WG reviews in yet, I'd say we easily have a
few weeks to work out whether there's really much to do; my take is:
it's two really small vocabularies, and it's adopting datalink/core
where it's pertinent.  To me, that sounds eminently feasible.  And
will make ProvDM a better and more useful standard.

        -- Markus