Malliavin differentiability of solutions of hyperbolic stochastic partial differential equations with irregular drifts
Antoine-Marie Bogso, Olivier Menoukeu Pamen
TL;DR
This work establishes strong well-posedness and Malliavin regularity for a two-parameter hyperbolic SPDE driven by a Brownian sheet with drift $b$ that is the difference of two componentwise monotone functions and exhibits spatial linear growth. The authors implement a Yamada–Watanabe strategy for Brownian sheets by proving path-by-path uniqueness via a Davie-type averaging estimate on the plane and a sheet-based Grönwall argument, leading to weak existence and hence a unique strong solution. They further prove Malliavin differentiability of the unique strong solution when $b$ is uniformly bounded, and obtain Malliavin regularity for small times under linear growth, leveraging Gaussian white noise techniques, local time-space integration formulas, and a robust compactness framework on the plane. The results extend existing work on one-parameter SDEs to hyperbolic SPDEs with irregular drifts, providing tools for density analysis and regularity in this broader stochastic PDE setting.
Abstract
We prove path-by-path uniqueness of solution to hyperbolic stochastic partial differential equations when the drift coefficient is the difference of two componentwise monotone Borel measurable functions of spatial linear growth. The Yamada-Watanabe principle for SDE driven by Brownian sheet then allows to derive strong uniqueness for such equation and thus extending the results in [Bogso, Dieye and Menoukeu Pamen, Elect. J. Probab., 27:1-26, 2022] and [Nualart and Tindel, Potential Anal., 7(3):661--680, 1997]. Assuming that the drift is globally bounded, we show that the unique strong solution is Malliavin differentiable. The case of spatial linear growth drift coefficient is also studied.
