Efficient simulation of a new class of Volterra-type SDEs
Ofelia Bonesini, Giorgia Callegaro, Martino Grasselli, Gilles Pagès
TL;DR
The paper introduces a convolution-kernel framework that lifts Volterra-type path-dependent SDEs to standard Markovian diffusions via a memory process $\xi$, with a reversible mapping back to the original process $X$. It proves strong existence, uniqueness, and path regularity for the coupled system, and shows that a carefully designed Euler-based scheme (Smart-Euler) achieves a strong convergence rate of $1/2$ for fractional kernels with $H\in(0,\tfrac{1}{2})$, independent of $H$. Specializing to fractional kernels highlights connections to rough volatility and the fractional Heston model, while maintaining finite-dimensional tractability for simulation. The work combines theoretical analysis with numerical illustrations, establishing both the feasibility and efficiency of the proposed method for memory-laden SVEs. Overall, the approach provides a robust, flexible toolkit for accurately simulating Volterra SDEs with memory and rough-path behavior, with significant implications for applications in biology, physics, and finance.
Abstract
We propose a new theoretical framework that exploits convolution kernels to transform a Volterra-type path-dependent (non-Markovian) stochastic process into a standard (Markovian) diffusion process. Remarkably, it is also possible to go back, i.e., the transformation is reversible. We discuss existence and path-wise regularity of solutions for our class of stochastic differential equations. In the fractional kernel case, when $H \in (0,\frac12)$, where $H$ is the Hurst coefficient, we propose a numerical simulation scheme which exhibits a remarkable strong convergence rate of order $1/2$, which constitutes a bold improvement when compared with the performance of available Euler schemes, whose strong rate of convergence is $H$.
