# [Maxima] tex() and multiplication

Matthew Sarnoff msarnoff at andrew.cmu.edu
Thu Jul 20 15:37:07 CDT 2006

Chris: (defprop mtimes "\\cdot " texsym) will put a dot between _any_
two expressions that are multiplied together. This makes expressions
like "2*3" look fine, but "2*x" and "'diff(y,x)" look strange.

Due to the many forms that the multiplication operator can take, I
think that the behavior of times should be extended in the following
way:

1. If the two expressions on either side of the operator are literal
numbers (i.e. numberp returns true), then "\\cdot " should be used.
2. If not, "\\," should be used, except:
3. In noun-forms of derivatives, no space at all (or very small
space) should be used in the denominator between the "d"/"\partial"
and the "x" variable. The current behavior (separate the two with the
"mtimes" symbol) looks a bit unclean.

Also, speaking of derivatives, I think that when formatting 'diff
(y,x), the "y" should be placed in the numerator if it is an atom.
That way, 'diff(y,x) would render nicely as

dy
--
dx

d
-- y
dx

I've found the functions in mactex.lisp (tex-nary and tex-d) that
need to be changed to accomodate this behavior, but I don't have
enough Lisp experience to implement it. Thought I'd suggest it, though.

-matt