Eigensystem ignoring assumptions
- To: mathgroup at smc.vnet.net
- Subject: [mg132281] Eigensystem ignoring assumptions
- From: Abced Def <ffcitatos at gmail.com>
- Date: Thu, 30 Jan 2014 23:04:40 -0500 (EST)
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Hi, I am trying to understand, why Eigensystem is ignoring the assumptions and still dividing by something that is explicitly assumed to be zero. This is a more extreme counterpart of the b>=0 case. Any comments or references to the documentation are appreciated. In[320]:= Clear["Global`*"] In[321]:= $Assumptions = b == 0; In[322]:= m1 = ({ {a, b}, {b, -a} }); In[323]:= Eigensystem[m1] Out[323]= {{-Sqrt[a^2 + b^2], Sqrt[ a^2 + b^2]}, {{-((-a + Sqrt[a^2 + b^2])/b), 1}, {-((-a - Sqrt[a^2 + b^2])/b), 1}}}