Exponential dichotomy and expansivity

Abstract

In this work we show if a linear nonautonomous system of ordinary differential equations satisfies a bounded growth condition, then it is exponentially expansive (a slightly stronger condition than uniformly noncritical as defined by Massera and Schäffer) on a half-line if and only if it has an exponential dichotomy and on a whole line if and only if it has an exponential dichotomy on both half-lines and no nontrivial bounded solution. We relate these theorems to Sacker and Sell's work on linear skew-product flows and also examine the robustness of exponential expansivity under perturbation.