Distribution-Dependent Stochastic Functional Differential Equations

By the approximation method introduced in \cite{FYW}, the existence and uniqueness are proved for a class of distribution-dependent stochastic functional differential equations (DDSFDEs). Moreover, combining the Harnack and shift-Harnack inequalities for classical stochastic functional differential equations with Girsanov’s theorem, Harnack and shift-Harnack inequalities are obtained for the non-linear semigroup $P_t^{\ast }$ associated to the functional solution.