Fokker-Planck equations for McKean-Vlasov SDEs driven by fractional Brownian motion
Saloua Labed, Nacira Agram, Bernt Oksendal
TL;DR
The paper addresses the distribution evolution of solutions to McKean–Vlasov SDEs driven by fractional Brownian motion with $H>1/2$. It derives a distributional Fokker–Planck equation for the law $\mu_t$, and gives a weak form that becomes a concrete PDE with time-dependent diffusion when $\mu_t$ has a density; it also establishes a fractional Feynman–Kac representation linking the forward FP equation to a backward Kolmogorov equation for functionals of the process. The framework uses a white-noise/Fourier approach with a Hilbert space of measures and fractional calculus to handle non-Markovian mean-field dynamics. Two illustrative examples—the law of fractional Brownian motion and a linear MV fractional SDE—demonstrate how fractional noise and mean-field interactions shape the evolution, yielding explicit FP, density, and Feynman–Kac representations.
Abstract
This paper investigates the probability distribution of solutions to McKean--Vlasov stochastic differential equations driven by fractional Brownian motion with Hurst parameter H>1/2. Our main contribution is the derivation of the associated Fokker--Planck equation, which characterizes the time evolution of the law of the solution in a suitable distributional framework. Under mild assumptions, we show that the law-valued process is absolutely continuous in time and provide an explicit weak formulation of the corresponding fractional McKean--Vlasov Fokker--Planck equation. In the case where the law admits a density, we obtain a more explicit partial differential equation with time-dependent diffusion coefficients induced by the fractional noise. We further establish a fractional Feynman--Kac representation, linking the forward Fokker--Planck equation with a backward Kolmogorov equation for functionals of the solution process. This result extends the classical Feynman--Kac framework to mean--field dynamics driven by fractional Brownian motion. To illustrate the theory, we analyze several explicit examples, including the law of fractional Brownian motion itself and linear McKean--Vlasov fractional SDEs. These examples highlight how fractional noise and mean--field interactions jointly affect the probabilistic and analytic structure of the system.
