Mathematik V, Universität Ulm, D-89069 Ulm, Germany ; Fachbereich Mathematik und Informatik, Martin-Luther- Universität Halle-Wittenberg, Theodor-Lieser-Str. 5, D-06120 Halle, Germany
Abstract:
A theorem of the Dore-Venni type for the sum of two closed linear operators is proved, where the operators are noncommuting but instead satisfy a certain commutator condition. This result is then applied to obtain optimal regularity results for parabolic evolution equations and evolutionary integral equations which are nonautonomous. The domains of the involved operators may depend on , but is required to satisfy a certain smoothness property. The results are then applied to parabolic partial differential and integro-differential equations.