Registries, IVO ids, and Data Set Identifiers (fwd)

[Robert Hanisch]

Does this idea make sense...?

The suite of telescope labels could function, and perhaps might more
properly function, as resource keys under a common authority, such as

    ivo://ads.harvard.edu/sa.cxo#2000

This allows the proposed dataset IDs to map virtually as-is onto the VO
registry Identifier, prefixed only by an authority ID which asserts,
properly, that an agreement with the journals and data centers defines the
range of resource keys.  It seems to me that this solves the persistence
problem, as the registries (or some other service) can be used to resolve
the ID into its associated URL, or service, or whatever.  Here I have
assumed that the ADS would act as the authority, though other possibilities
come to mind, such as having IVOA itself assume this role for such a broad
matter.  In that case we might have

    ivo://ivo.net/sa.cxo#2000

However, given the well-established role of the ADS I think the first form
is preferable.

The drawback, perhaps, is that there are now at least two identifiers for a
particular data set, such as

    ivo://sao.harvard.edu/cxo#2000
and
    ivo://ads.harvard.edu/sa.cxo#2000

since both data centers and ADS/astronomy journals will wish to publish
their collections in the registry.  We will have different identifiers
already, though, for mirrors, so this in itself is not a fatal problem.  The
RM schema includes elements Relationship and RelationshipID that can be used
to explicitly capture the "mirror-of" status, as in

    Identifier = ivo://sao.harvard.edu/cxo#2000

and another,

    Identifier = ivo://ads.harvard.edu/sa.cxo#2000
    Relationship = mirror-of
    RelationshipID = ivo://sao.harvard.edu/cxo#2000

I don't think it is absolutely necessary to indicate the relationship shown
above, but the mechanism is available to us.

Is this is a way to reconcile the needs of the generic VO registry with the
needs of the journal article/dataset links?

Bob