[texhax] Multiple column math equations with tags / multicols questions

[Johan Glimming]

Hello

I would like to typeset equations of the form

  eqn1   (tag1)        eqn2 (tag2)         eqn3 (tag3)

i.e. would like to have more than one tag per line. Using
multicols is tempting, but requires a lot of manual work
because

1. When I enter math mode in multicols a lot of space is
    inserted before the first paragraph inside multicols
    giving me

                          eqn2 (tag2)         eqn4 (tag4)
     eqn1   (tag1)        eqn3 (tag3)         eqn5 (tag5)

2. I typically have a bunch of equations of various with,
    and want them to take as little space as possible by
    putting them on multiple columns (the equations are
    inference rules etc). Preferrably, I would like an
    environment that decides for me when to break the
    equations to several columns and where to break them,
    e.g. giving me

          equation_0_is_terribly_terribly_length (tag0)
      eqn1   (tag1)        eqn2 (tag2)         eqn3 (tag3)
      equation_4_is_medium (tag4)  equation_5_is_medium (tag4)

Does anyone have a solution or suggestion?

Med vänliga hälsningar / Yours Sincerely,
Johan Glimming