A Note on Similarity to Contraction for Stable Companion (2 × 2)-Matrices.

We consider companion matrices of size 2 × 2 with general complex spectra satisfying a root condition with respect to the closed complex unit circle or the closed complex left half plane. For both cases, smooth and naturally conditioned basis transformations are constructed such that the resulting, transformed matrix is contracting or dissipative, respectively, with respect to the ℓ -norm. [ABSTRACT FROM AUTHOR]