Non-Sturmian sequences of matrices providing the maximum growth rate of matrix products

Abstract

One of the most pressing problems in modern analysis is the study of the growth rate of the norms of all possible matrix products Ai n • • • Ai 0 with factors from a set of matrices A . So far, only for a relatively small number of classes of matrices A has it been possible to rigorously describe the sequences of matrices {Ai n } that guarantee the maximal growth rate of the corresponding norms. Moreover, in almost all theoretically studied cases, the index sequences {in} of matrices maximizing the norms of the corresponding matrix products turned out to be periodic or so-called Sturmian sequences, which entails a whole set of "good" properties of the sequences {Ai n }, in particular the existence of a limiting frequency of occurrence of each matrix factor Ai ∈ A in them. The paper determines a class of 2 × 2 matrices consisting of two matrices similar to rotations of the plane in which the sequence {Ai n } maximizing the growth rate of the norms Ai n • • • Ai 0 is not Sturmian. All considerations are based on numerical modeling and cannot be considered mathematically rigorous in this part. Rather, they should be interpreted as a set of questions for further comprehensive theoretical analysis.