[texhax] Bold math characters

[Michael Barr]

>From reading the Latex Companion (Second printing, 1994), page 179, one
would expect that
{\mathversion{bold} $a$}
and
$\mathbf a$
would produce the same output.  But they don't.  The first gives a bold
version of the \mit a and the second a bold upright a.  Suppose you have
a more complicated formula that you want the first kind of a, but
nothing else bold.  Is there an easy way to do it?

Michael Barr