Linear maps preserving the Lorentz spectrum: The $2\times 2$ case

M. I. Bueno, Susana Furtado, Aelita Klausmeier +1

In this paper a complete description of the linear maps $\varphi :W_n\to W_n$ that preserve the Lorentz spectrum is given when $n=2$ and $W_n$ is the space $M_n$ of $n\tim…