Timothy,

 > But shouldn't it be reasonably difficult to use unusual symbols within math?
 > There seems to me nothing wrong with requiring a special definition
 > of math symbols.

no there isn't. i only pointed out that if there aren't any, one has to make
some or else on get's a suitable error: not possible to use in math

 > I didn't really understand the mention of cyrillic in this context --
 > are these russian letters to be used with mathematical meanings?
 > As far as I know, even Russian mathematicians don't use cyrillic
 > in their maths (though I could be wrong about that).

well Vladimir is certainly able to say so with more authority but to my
knowledge people use cyrillic letters (and greek definitely). perhaps not when
the write up for a US or Irish journal though :-)

 > a one-line explanation of my misunderstanding would suffice.

here we go :-) what is tried to allow people to use their keys on their
keyboards both for text as well as for math with suitable definitions if in
math context.

frank