#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-4.7.1
Component: symbolics | Keywords: inequality equality
relational sd31 __richcmp__
Work_issues: | Upstream: N/A
Reviewer: Karl-Dieter Crisman | Author: Keshav Kini, Burcin
Erocal
Merged: | Dependencies:
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Comment(by kcrisman):
{{{
-x+y >0 is not the same as y > x
}}}
Correct. We use the philosophy (used elsewhere) that a comparison is True
if you can prove it is True, and that otherwise it is False. False means
that we can't prove it's True, and in general these kinds of
simplifications are super hard. So all your examples need to be False,
sadly.
As for the thing that breaks... I agree that is a problem. Great catch!
Can you put your (real) name as a reviewer? (You should also feel free to
add yourself to the [http://trac.sagemath.org/sage_trac/ main Trac page]
as a developer/contributor.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11309#comment:25>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
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