Testing xCAS version 1.2.3-9 (2017)

[DrD]

I was doing something somewhat related to this topic, in CAS, which resulted in the warning message below. Is this perhaps related?

Warning: the test a==b is performed by checking that the internal representation of regroup(a-b) is not 0. Therefore a==b may return false even if a and b are mathematically equal, if they have different internal representations.
You can explicitly call a simplification function like simplify(a-b)==0 to avoid this.
Warning, argument is not an equation, solving 0=0

This warning only pops up the first time my statement was processed, afterwards only the "Warning, argument is not an equation, solving 0=0" shows up.

In my case, it was this snippet, which produces different results when used on the EMU and HC:
(interesting: regroup(a,b) is a working, but uncatalogued, (internal), prime CAS command.)

Code:


a:="2x+y=10";
solve(subst(EXPR(a),x = 60),y);  ==> {-110} on HC and [[]] on EMU