#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: needs_work
Priority: major |
Milestone: sage-5.0
Component: symbolics |
Resolution:
Keywords: inequality equality relational sd31 __richcmp__ | 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 kcrisman):
This still applies, and fixes another issue.
{{{
sage: c = (x-2<=0)
sage: assume(c)
sage: a = (x-1<=0)
sage: if a in sage.symbolic.assumptions._assumptions:
....: print 'yes'
....:
sage: assumptions()
[x - 2 <= 0]
sage: assume(a)
sage: assumptions()
[x - 2 <= 0, x - 1 <= 0]
}}}
Before, the second assumption didn't obtain, because currently
{{{
sage: c = (x-2<=0)
sage: L = [c]
sage: L
[x - 2 <= 0]
sage: a = (x-1<=0)
sage: a in L
True
}}}
which is not good. See [https://groups.google.com/forum/#!topic/sage-
support/H-QcXkNCajM this sage-support thread].
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11309#comment:33>
Sage <http://www.sagemath.org>
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