Nonuniform-Grid Markov Chain Approximation of Continuous Processes with Time-Linear Moments

Fuente: arXiv
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Auteurs principaux: Kim, Do Hyun, Cetinkaya, Ahmet
Format: Preprint
Publié: 2025
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author Kim, Do Hyun
Cetinkaya, Ahmet
author_facet Kim, Do Hyun
Cetinkaya, Ahmet
contents We propose a method to approximate continuous-time, continuous-state stochastic processes by a discrete-time Markov chain defined on a nonuniform grid. Our method provides exact moment matching for processes whose first and second moments are linear functions of time. In particular, we show that, under certain conditions, the transition probabilities of a Markov chain can be chosen so that its first two moments match prescribed linear functions of time. These conditions depend on the grid points of the Markov chain and the coefficients of the linear mean and variance functions. Our proof relies on two recurrence relations for the expectation and variance across time. This approach enables simulation-based numerical analysis of continuous processes while preserving their key characteristics. We illustrate its efficacy by approximating continuous processes describing heat diffusion and geometric Brownian motion (GBM). For heat diffusion, we show that the heat profile at a set of points can be investigated by embedding those points inside the nonuniform grid of our Markov chain. For GBM, numerical simulations demonstrate that our approach, combined with suitable nonuniform grids, yields accurate approximations, with consistently small empirical Wasserstein-1 distances at long time horizons.
format Preprint
id arxiv_https___arxiv_org_abs_2511_20416
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Nonuniform-Grid Markov Chain Approximation of Continuous Processes with Time-Linear Moments
Kim, Do Hyun
Cetinkaya, Ahmet
Probability
Systems and Control
Dynamical Systems
Computation
We propose a method to approximate continuous-time, continuous-state stochastic processes by a discrete-time Markov chain defined on a nonuniform grid. Our method provides exact moment matching for processes whose first and second moments are linear functions of time. In particular, we show that, under certain conditions, the transition probabilities of a Markov chain can be chosen so that its first two moments match prescribed linear functions of time. These conditions depend on the grid points of the Markov chain and the coefficients of the linear mean and variance functions. Our proof relies on two recurrence relations for the expectation and variance across time. This approach enables simulation-based numerical analysis of continuous processes while preserving their key characteristics. We illustrate its efficacy by approximating continuous processes describing heat diffusion and geometric Brownian motion (GBM). For heat diffusion, we show that the heat profile at a set of points can be investigated by embedding those points inside the nonuniform grid of our Markov chain. For GBM, numerical simulations demonstrate that our approach, combined with suitable nonuniform grids, yields accurate approximations, with consistently small empirical Wasserstein-1 distances at long time horizons.
title Nonuniform-Grid Markov Chain Approximation of Continuous Processes with Time-Linear Moments
topic Probability
Systems and Control
Dynamical Systems
Computation
url https://arxiv.org/abs/2511.20416