[VEP-003] datalink/core#sibling: Ready for TCG

[François Bonnarel]

Hi all,


Le 12/02/2020 à 14:15, Markus Demleitner a écrit :
> Dear DAL,
>
> In December, we discussed about VEP-003
> (https://volute.g-vo.org/svn/trunk/projects/semantics/veps/VEP-003.txt),
> which would add a term #sibling to the datalink vocabulary.
>
> Discussion sort of ended with
> http://mail.ivoa.net/pipermail/dal/2020-January/008257.html -- and
> now I'm not sure whether there are still doubts if #sibling should go
> ahead.  Are there?
Yes I told  you I don't think this covers all the cases where wou want 
to associate a dataset to a source in a catalog.
Just because as you say below sibling means they have the same origin.
What we had in mind is something where they are simply cross-corelated.

Is CrossedDataSet something we could consider a head in branch 
containing sibling, contains, followup ?
Cheers
François

>
> There was also
> http://mail.ivoa.net/pipermail/dal/2020-January/008258.html, in which
> Pat suggests #contains and #followup in roughly the same context.  Do
> people see these as entangled with #sibling or can we go ahead with
> it before thinking more carefully about the other two?
>
> Me, I'd say #contains and #followup may make sense but just don't
> match the showcase example for #sibling, the RP/BP spectra and epoch
> photometry[1] in Gaia.  These are simply parallel products to the
> gaia_source row (which, incidentally, I'd have no qualms to call a
> "dataset", too).  They very certainly are not contained in the
> gaia_source row, and they're not followups: All these items are
> derived from the same observations, although perhaps in different
> ways.
>
>           -- Markus
>
> [1] You might call the epoch photometry a #progenitor (though I don't
> think that's true in the strict provenance sense) -- but let's
> disregard that here.