Lipschitz Continuity Results for Minimax Solutions of Path-Dependent Hamilton--Jacobi Equations

We consider a Cauchy problem for a (first-order) path-dependent Hamilton–Jacobi equation with coinvariant derivatives and a right-end boundary condition. Such problems arise naturally in the study of properties of the value functional in (deterministic) optimal control problems and differential games for time-delay systems. We prove that, under certain assumptions on the Hamiltonian and the boundary functional, a minimax (generalized) solution of the Cauchy problem satisfies Lipschitz conditions both in time and functional variables. In the latter case, Lipschitz conditions are formulated with respect to the uniform norm and some special norm of the space of continuous functions.