[Maxima] Bug report ID 2123651 "min and max of imaginary and real numbers"

[Barton Willis]

When a is on the imaginary axis, max(%i*a,3) is just fine. So a nounform is OK.

 (%i3) max(%i*a, 3);
 (%o3) max(3,%i*a)

Not useful or informative:

 (%i4) compare(%i*a,3);
 (%o4) notcomparable

Maybe compare shouldn't be a user-level function (private to simp-max and simp-min).

--bw