[Maxima] need help with MGRP bug

[Robert Dodier]

Hello, while I was looking at something else, I stumbled over this ...

?mgrp(x,1);
 => x - 1 > 0
?mgrp(1,x);
 => x - 1 > 0

Oops, those two shouldn't be the same. The first one is OK
and the second one is reversed.
This result dates back to 5.11.0 at least (I wasn't able to test it
with anything older).

I believe the problem might be somewhere in SIGN1.
The relevant functions appear to be SIGN DCOMPARE COMPSPLT
C-$POS SIGN1 SUB* MGRP MEVALP2 MEVALP1 MEVALP.

I'll continue to look at this but in the meantime maybe someone
else can take a look.

best
Robert