#11309: Sage sees - x + y > 0, - y + x >= 0, and x - y > 0 as equivalent
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Reporter: tnv |
Owner: burcin
Type: defect |
Status: positive_review
Priority: major |
Milestone: sage-5.1
Component: symbolics |
Resolution:
Keywords: inequality equality relational sd31 __richcmp__ sd40.5 |
Work issues:
Report Upstream: N/A |
Reviewers: Karl-Dieter Crisman, ThanhVu Nguyen
Authors: Keshav Kini, Burcin Erocal |
Merged in:
Dependencies: |
Stopgaps:
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Comment (by burcin):
Replying to [comment:53 tnv]:
>
> The main reason why I report this in the first place is because of this
error in which multiplying by -1 does not switch the sign. I think they
are related but not sure.
>
> {{{
> sage: -1 * (x<5)
> -x < -5
> }}}
This is #7660. It would be quite easy to remove the `if
is_a_relational(left._gobj)` checks in `_add_, `_mul_`, etc. in
`sage/symbolic/expression.pyx` to revert back to GiNaC behavior.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11309#comment:55>
Sage <http://www.sagemath.org>
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