ASKSAGE: Sage Q&A Forum - Individual question feedhttp://ask.sagemath.org/questions/Q&A Forum for SageenCopyright Sage, 2010. Some rights reserved under creative commons license.Wed, 01 Apr 2015 05:12:17 -0500Test if an inequality is feasible under assumptionshttp://ask.sagemath.org/question/26410/test-if-an-inequality-is-feasible-under-assumptions/I want to test if an inequality system is feasible under non-negativity assumptions. I run into the problem that the assumptions seem not be used by the inequality solver. Here is a minimal example
sage: (l1,l2) = var("l1 l2")
sage: assume (l1>=0)
sage: assume (l2>=0)
sage: solve (l1*l2<0, [l1,l2])
[[l1 < 0, 0 < l2], [0 < l1, l2 < 0]]
Is it possible to have the solver use the assumptions and determine infeasibility of the system? Wed, 01 Apr 2015 05:03:33 -0500http://ask.sagemath.org/question/26410/test-if-an-inequality-is-feasible-under-assumptions/Answer by Thomas for <p>I want to test if an inequality system is feasible under non-negativity assumptions. I run into the problem that the assumptions seem not be used by the inequality solver. Here is a minimal example</p>
<pre><code>sage: (l1,l2) = var("l1 l2")
sage: assume (l1>=0)
sage: assume (l2>=0)
sage: solve (l1*l2<0, [l1,l2])
[[l1 < 0, 0 < l2], [0 < l1, l2 < 0]]
</code></pre>
<p>Is it possible to have the solver use the assumptions and determine infeasibility of the system? </p>
http://ask.sagemath.org/question/26410/test-if-an-inequality-is-feasible-under-assumptions/?answer=26412#post-id-26412This seems to be the answer: http://trac.sagemath.org/ticket/6515 Wed, 01 Apr 2015 05:12:17 -0500http://ask.sagemath.org/question/26410/test-if-an-inequality-is-feasible-under-assumptions/?answer=26412#post-id-26412