[texhax] On \qed macros

[Barbara Beeton]

    Firstly, my thanks to those who have provided input to this question,
    and my apologies for those of you who have been distracted by it.

it's really a rather nasty problem to get
something that's both robust and works in
all possible situations.

i think no one has mentioned that this is
built in to the amsthm package, for which
it is automatically dropped in at the end
of the proof environment.  (thus it is not
a standalone solution.)  there is also the
enhancement \qedhere which can be used when
a proof ends with either a list or a display
when the box normally drops down to a line
by itself (but always flush right).  by
putting \qedhere as the last thing within
the list or display environment, the box
is brought up to the final line; this does
require the use of left-hand equation
numbers (the default for ams document
classes).  the code is pretty nasty, but
comments in amsclass.dtx (from which amsthm
and the documentclasses are generated) are
helpful.  all this is due to michael downes,
to whom we owe a great deal.
							-- bb