ON THE APPROXIMATE CONTROLLABILITY OF SOME SEMILINEAR PARTIAL FUNCTIONAL INTEGRODIFFERENTIAL EQUATIONS WITH UNBOUNDED DELAY

This work concerns the study of the approximate controllability for some nonlinear partial functional integrodifferential equation with infinite delay arising in the modelling of materials with memory, in the framework of Hilbert spaces. We give sufficient conditions that ensure the approximate controllability of the system by supposing that its linear undelayed part is approximately controllable, admits a resolvent operator in the sense of Grimmer, and by making use of the measure of noncompactness and the Monch fixed-point Theorem. As a result, we obtain a generalization of several important results in the literature, without assuming the compactness of the resolvent operator. An example of applications is given for illustration.