文摘
We consider the necessary conditions for Nash-points of Vlasov-McKean functionals \(\mathcal {J}^{i}[\mathbf{v}]=\int _{Q}mf^{i}(\cdot ,m,\mathbf{v})\,dx\,dt\) (\(i=1,...,N\)). The corresponding payoffs \(f^{i}\) depend on the controls \(\mathbf{v}\) and, in addition, on the field variable \(m=m(\mathbf{v})\). The necessary conditions lead to a coupled forward-backward system of nonlinear parabolic equations, motivated by stochastic differential games. The payoffs may have a critical nonlinearity of quadratic growth and any polynomial growth w.r.t. m is allowed as long as it can be dominated by the controls in a certain sense. We show existence and regularity of solutions to these mean-field-dependent Bellman systems by a purely analytical approach, no tools from stochastics are needed.KeywordsNonlinear parabolic systemsBellman equationsStochastic differential gamesMean field dependence