Periodic measures of stochastic delay lattice systems

The periodic measures of the stochastic delay reaction-diffusion lattice systems are investigated. Under a general condition, we prove the existence of periodic measures when the time-dependent terms of the system are periodic in time. Under further assumptions on the nonlinear terms, we show the set of all periodic measures of the perturbed system is weakly compact. Finally, we prove every limit point of a sequence of periodic measures of the stochastic delay system must be a periodic measure of the limiting system as the noise intensity or the time delay goes to zero. (C) 2020 Elsevier Inc. All rights reserved.