Discrete stochastic maximal regularity
Foivos Evangelopoulos-Ntemiris, Mark Veraar
TL;DR
<3-5 sentence high-level summary> This work develops a comprehensive framework for discrete stochastic maximal regularity (DSMR) in time-discretized parabolic SPDEs and establishes a precise equivalence with the continuous stochastic maximal L^p-regularity (SMR) for a broad class of schemes, including exponential Euler and stable rational methods. The authors build a robust toolkit based on sectorial operators, $H^∞$-calculus, and $R$-boundedness to prove DSMR, permanence, and weighted extrapolation properties, and they derive a sharp maximal estimate in the trace space $D_A(1-rac{1}{p},p)$ that incorporates parabolic smoothing. A key contribution is showing that DSMR for a scheme is necessary and sufficient for SMR of the generator, enabling transfer of continuous-time results to the discrete setting and yielding wide-ranging DSMR consequences across Hilbert and L^q spaces. The results pave the way for improved convergence and stability analyses of time-discrete schemes for SPDEs and provide deep insights into discrete stochastic smoothing phenomena.
Abstract
In this paper, we investigate discrete regularity estimates for a broad class of temporal numerical schemes for parabolic stochastic evolution equations. We provide a characterization of discrete stochastic maximal $\ell^p$-regularity in terms of its continuous counterpart, thereby establishing a unified framework that yields numerous new discrete regularity results. Moreover, as a consequence of the continuous-time theory, we establish several important properties of discrete stochastic maximal regularity such as extrapolation in the exponent $p$ and with respect to a power weight. Furthermore, employing the $H^\infty$-functional calculus, we derive a powerful discrete maximal estimate in the trace space norm $D_A(1-\frac1p,p)$ for $p \in [2,\infty)$.
