Doctest: Incorrect zero test of complex symbolic expressions

[mezzarobba]

This is fixed but needs a doctest:

Yet another example where symbolic expressions are abusively considered equivalent, even though simplify() has become a bit more careful.

sage: var('a,x')
(a, x)
sage: assume(a, 'complex')
sage: assume(x, 'complex')
sage: expr = a^(4*x) - (a^4)^x
sage: expr.is_zero()
True
sage: expr(a=I, x=1/2)
-2

Component: symbolics

Author: Ralf Stephan

Branch/Commit: 9974eef

Reviewer: Karl-Dieter Crisman

Issue created by migration from https://trac.sagemath.org/ticket/15571

[rwst]

comment:4

Appears to having been fixed and also already included in Sage.

[rwst]

Branch: u/rws/doctest__incorrect_zero_test_of_complex_symbolic_expressions

[rwst]

Commit: 9974eef

[rwst]

New commits:

9974eef

15571: add doctest

[rwst]

Author: Ralf Stephan

[kcrisman]

Reviewer: Karl-Dieter Crisman

[kcrisman]

comment:8

Indeed, one doesn't have to do any assumption at all to get the 'false' now.

sage: sage: var('a,x')
(a, x)
sage: (a, x)
(a, x)
sage: sage: expr = a^(4*x) - (a^4)^x
sage: sage: expr.is_zero()
False

If you want to remove the second

+            sage: assume(a, 'complex')
+            sage: assume(x, 'complex')

and then the forget() which I think is all superfluous, that would be great, but it's fine this way too.

[vbraun]

Changed branch from u/rws/doctest__incorrect_zero_test_of_complex_symbolic_expressions to 9974eef