PUB - Publikationen an der Universität Bielefeld

In this work we provide detailed estimates of maximal principal angles between subspaces and we analyse their smoothness for smoothly varying subspaces. This leads to a new definition of angular values for linear dynamical systems in continuous time. We derive some of their properties complementary to the theory of angular values developed in Beyn, et al. [Angular values of nonautonomous and random linear dynamical systems: Part I - fundamentals, SIAM J. Appl. Dyn. Syst. 21(2) (2022), pp. 1245-1286; Angular values of nonautonomous linear dynamical systems: Part II - reduction theory and algorithm, SIAM J. Appl. Dyn. Syst. 22(1) (2023), pp. 162-198] for discrete time systems. The estimates are further employed to establish upper semicontinuity of angular values for some parametric model examples of discrete and continuous type.