  The work is about homogenization for a type of multivalued Dirichlet-Neumann
problems. First, we prove an average principle for general multivalued
stochastic differential equations in the weak sense. Then for general
forward-backward coupled multivalued stochastic systems, the other average
principle is presented. Finally, we apply the result to a type of multivalued
Dirichlet-Neumann problems and investigate its homogenization.
