Participants : Omar, Matthew, Pierre, Markus, Jesus, Gerard, Pat, Mireille (Minutes).

Discussion took place between MD and GL (Feb, 1st, 2013); it seems the remaining differences are due to differing emphasis on one of the two use cases:

1. Find instances of the same "elementary" objects (e.g., a position) using the utype alone (Gerard's); deeply nested groups and making utypes references directly into VO-DML works better here.
2. Find "roles" (like "RA of target object" as opposed to "RA of observation center") using plain string comparsions (Markus's use case , and many developers for clients accessing various data collections, existing TAP services, etc.); here, attribute.attribute.attribute is practically required.

OL: probably both are needed, and with VO-DML both can be covered..

GL: At least in a VOTable serialisation what (2) does isn't that much harder in (1). Even with XSLT, you can find a group with 'Utype contains Target' and find the coordinates of the position in there. The 2 coordinates will be grouped in the code data structure anyway. TAP schema has no grouping property for the moment, but this could be added.

GL: Could we try to first consider the general problem of “Mapping of a DM for VOtable”, and then consider how we can simplify this to cover the 'flat string' use-case, possibly by allowing a utype string as attribute of attribute of a datatype structure.

MD: Suggests to wait for everyone to read the new Gerard's VO-DML +Utype+VOtable document, then launch a deeper discussion.

GL: Should we propose meta-modelling as a thing the IVOA formally tasks the DM WG with?

MG: What are the impacts on various models: existing ones and new ones?

New ones should follow the new rules set up in the VO-DML exercise, old ones can just continue to exist.

MG and others: old ones should still be usable with existing utypes as defined in the specs

Action items:

All, with a special help from Gerard : check all use-cases: are they supported by the VO-DML approach or not .

MD and MG: complete last editing steps for ‘Current usage’ document before Exec meeting on Feb 27th.

JS, GL, ML: proceed on PhotDMv1-1 UML validation in VODML and VO-DML utypes generation.

then JS: PhotDMv1-1 RFC to restart/refresh

Next Telecon: Tuesday Feb, 19th, 2013, 17:00 UTC