ON THE TRACE CHARACTERIZATION OF THE JOINT SPECTRAL RADIUS

A characterization of the joint spectral radius, due to Chen and Zhou, relies on the limit superior of the k-th root of the dominant trace over products of matrices of length k. In this note, a sufficient condition is given such that the limit superior takes the form of a limit. This result is useful while estimating the joint spectral radius. Although it applies to a restricted class of matrices, it appears to be relevant to many realistic situations.