[mdx] MDQ questions

[Tom Scavo]

On Mon, Nov 25, 2013 at 11:13 AM, Ian Young <ian at iay.org.uk> wrote:
>
> Coming back to my quoted paragraph above, though, and this is really a question for all: *can* anyone think of a real use case for the union operator that isn't covered by IDs that designate arbitrary groups? If not, I am tempted to suggest that we consider dropping it entirely; it would simplify a lot of the questions about encoding the '+' and the like.

Ian, since we are coming back to this after a long hiatus, would you
mind rephrasing the question in its entirety? (As it stands, I can
only think of questions, not answers.)

Thanks,

Tom