Matrix equations
- To: mathgroup at smc.vnet.net
- Subject: [mg53862] Matrix equations
- From: Jamie Vicary <jamievicary at gmail.com>
- Date: Tue, 1 Feb 2005 04:08:12 -0500 (EST)
- Organization: University of Cambridge, England
- Sender: owner-wri-mathgroup at wolfram.com
Hi there,
I'm using Mathematica 5.1 and trying to solve equations like the
following:
A.{{1,0},{0,2}} == -{{1,0},{0,2}}.A
i.e. I want to find the matrix that anticommutes with {{1,0},{0,2}}. The
only matrix that solves this is the zero matrix {{0,0},{0,0}} but
Mathematica refuses to solve the above equation for A, giving the usual
"The equations appear to involve the variables to be solved for in an
essentially non-algebraic way."
If I set A={{a,b},{c,d}} and then solve the above equation for
{{a,b},{c,d}} then Mathematica correctly tells me {{a->0, b->0, c->0,
d->0}}, but this isn't what I want. I want to give Mathematica equations
in terms of matrices, not in terms of their components.
In summary: why, when I give Mathematica the above equation to
solve for A, does it not solve it giving A->{{0,0},{0,0}} which is the
trivial, unique solution to the equation?
Thanks,
Jamie Vicary.