The author gives a new characterization of evolution families of operators in Banach spaces that have exponential dichotomy. The framework is similar to that of N. V. Minh, F. Räbiger and R. Schnaubelt [Integral Equations Oper. Theory 32, 332-353 (1998; Zbl 0977.34056)], based on the so-called “evolution semigroup” associated to an evolution family. In that paper, the exponential dichotomy of an evolution family was characterized in terms of inversion properties of a suitably defined operator, , associated to the solutions of the integral equation
In the paper under consideration, the characterization is still given in terms of the operator but a different characterizing property is considered which is based on the concepts of “exponentially dichotomous” and “quasi-exponentially dichotomous” operators, the latter being introduced by the author.
The new result allows the author to extend to a general Banach space results proved for finite-dimensional spaces by A. Ben-Artzi, I. Gohberg and M. A. Kaashoek [J. Dyn. Differ. Equations 5, 1-36 (1993; Zbl 0771.34011)].