Stochastic Volterra integral equations driven by $ G $-Brownian motion
Bingru Zhao, Renxing Li, Mingshang Hu
TL;DR
The paper studies stochastic Volterra integral equations driven by $G$-Brownian motion ($G$-SVIE), establishing existence, uniqueness, and two notions of continuity for solutions under mild growth and continuity assumptions. It introduces a contraction-mapping framework in the $G$-expectation setting and proves mean-square and pathwise continuity, along with a priori stability estimates. A central contribution is a comparison theorem for $G$-SVIEs with separable diffusion coefficients, achieved via a new quasilinearization technique and a two-step approximation that relaxes classical differentiability requirements of coefficients. These results advance robust stochastic analysis under model uncertainty and memory effects, with a concrete linear example illustrating the applicability of the methods.
Abstract
In this paper, we study the stochastic Volterra integral equation driven by $G$-Brownian motion ($G$-SVIE). The existence, uniqueness and two types of continuity of the solution to $G$-SVIE are obtained. Moreover, combining a new quasilinearization technique with the two-step approximation method, we establish the corresponding comparison theorem for a class of $G$-SVIEs. In particular, by means of this method, the classical assumptions on partial derivatives of the coefficients are unnecessary.
