Special Session 168: Stochastic Analysis and Large Scale Interacting Systems

Stochastic Maximum Principle for Delay Equations: the Non-Convex Case
giuseppina guatteri
Politecnico di Milano
Italy
Co-Author(s):    Federica Masiero
Abstract:
This talk is based on joint work with Federica Masiero. We discuss a stochastic maximum principle for controlled stochastic differential equations with delay in the state, control-dependent noise, and non-convex control sets. The cost functional may depend on both the present state and its weighted past through general finite measures. In the regular case, where the delay measures admit square-integrable densities, the problem can be reformulated as an infinite-dimensional stochastic evolution equation in a Hilbert space, and necessary optimality conditions are derived through spike variation and first- and second-order adjoint equations. For general finite measures, including pointwise delays, the analysis combines anticipated backward stochastic differential equations with an approximation procedure for the second-order term. This yields a stochastic maximum principle beyond the convex setting and clarifies the role of infinite-dimensional methods in delay control problems.