Simulation and approximationof Lévy-driven stochastic differential equations

Abstract

We consider the approximate Euler scheme for Lévy-drivenstochastic differential equations.We study the rate of convergence in law of the paths.We show that when approximating the small jumps by Gaussianvariables, the convergence is much faster than when simplyneglecting them.For example, when the Lévy measure of the driving processbehaves like |z|^−1−αdz near 0, for some α ∈ (1,2), we obtain an error of order 1/√n with a computational cost of order n^α. For a similar error when neglecting the small jumps, see[S. Rubenthaler, Numerical simulation of the solution of a stochastic differential equation driven by a Lévy process. Stochastic Process. Appl. 103 (2003) 311–349], the computational cost is of ordern^α/(2−α), which is huge when α is close to 2. In the same spirit, we study the problem of the approximation of a Lévy-driven S.D.E.by a Brownian S.D.E. when the Lévy process has no large jumps. Our results rely on some results of [E. Rio, Upper bounds for minimal distances in the central limit theorem. Ann. Inst. Henri Poincaré Probab. Stat. 45 (2009) 802–817] about the central limit theorem, in the spirit of the famous paper by Komlós-Major-Tsunády [J. Komlós, P. Major and G. Tusnády, An approximation of partial sums of independentrvs and the sample df I. Z. Wahrsch. verw. Gebiete 32 (1975) 111–131].