On viscosity solutions of path-dependent Hamilton-Jacobi-Bellman-Isaacs equations for fractional-order systems

This paper deals with a two-person zero-sum differential game for a dynamical system described by a Caputo fractional differential equation of order alpha is an element of (0, 1) and a Bolza cost functional. The differential game is associated to the Cauchy problem for the path-dependent Hamilton-Jacobi-Bellman-Isaacs equation with so-called fractional coinvariant derivatives of order alpha and the corresponding right-end boundary condition. A notion of a viscosity solution of the Cauchy problem is introduced, and the value functional of the differential game is characterized as a unique viscosity solution of this problem. (c) 2024 Elsevier Inc. All rights reserved.