On the periodic solutions for some retarded partial differential equations by the use of semi-Fredholm operators

The main goal of this work is to examine the periodic dynamic behavior of some retarded periodic partial differential equations (PDE). Taking into consideration that the linear part realizes the Hille-Yosida condition, we discuss the Masseras problem to this class of equations. Especially, we use the perturbation theory of semi-Fredholm operators and the Chow and Hales fixed point theorem to study the relation between the boundedness and the periodicity of solutions for some inhomogeneous linear retarded PDE. An example is also given at the end of this work to show the applicability of our theoretical results.