Doctest: x.is_negative() when assuming x < 0

[pelegm]

I understand the is_negative flag is still experimental. I just document it here, and mention that is_positive does work as expected when assuming x > 0.
Here's an example:

sage: var('x,y')
sage: assume(x>0)
sage: assume(y<0)
sage: x.is_positive()
True
sage: y.is_negative()
False

Tested on 7.5.beta4.

Depends on #23325

Component: symbolics

Keywords: is_negative

Author: Ralf Stephan

Branch/Commit: 5db378f

Reviewer: Jeroen Demeyer

Issue created by migration from https://trac.sagemath.org/ticket/21973

[rwst]

comment:1

Reported as pynac/pynac#220

[rwst]

Dependencies: pynac-0.7.9

[rwst]

Changed dependencies from pynac-0.7.9 to #23325

[rwst]

Branch: u/rws/doctest__x_is_negative___when_assuming_x___0

[rwst]

New commits:

5db378f

21973: Doctest: x.is_negative() when assuming x < 0

[rwst]

Author: Ralf Stephan

[rwst]

Description changed:

--- 
+++ 
@@ -7,7 +7,7 @@
 sage: assume(y<0)
 sage: x.is_positive()
 True
-sage: x.is_negative()
+sage: y.is_negative()
 False
 ```
 

[rwst]

Commit: 5db378f