Continuity and averaging for parabolic evolution systems

Averaging principle for abstract non-autonomous parabolic evolution equations governed by time-dependent family of positive sectorial operators is proved. Apart from linear case also a nonlinear version for continuous perturbations is provided. These results extend Henry's averaging technique to the case where linear part of the equation depends on time and results due to Ilyin that were for dissipative equations.47D06, 34G05, 34G20