The relaxation time does not control the normal approximation of stationary additive functionals

Let $X$ be a finite irreducible reversible Markov chain in continuous time with relaxation time $\tau_2$, started from its stationary distribution, and let $g$ be a function on its states with mean $0$ and variance $1$ under that distribution. Aldous and Fill asked whether the Kolmogorov distance between $\int_0^tg(X_u)\,du/(\sigma t^{1/2})$, where $\sigma^2$ is the asymptotic variance rate, and the standard normal law is bounded by a function of $\max|g|$ and $t/\tau_2$ alone that tends to $0$ as $t/\tau_2\to\infty$. It is not. For every $b\ge1$ and $s\ge2b$ there are a chain on four states with $\tau_2=1$ and a function $g$ of mean $0$ and variance $1$ with $\max|g|=b$ such that $\int_0^sg(X_u)\,du\le0$ with probability at least $1-4/s$, so at $t=s$ the distance is at least $1/2-4/s$ whatever positive constant the integral is divided by.

Authors

Institutions

Publication Details

Journal
Zenodo (CERN European Organization for Nuclear Research)
Published
2026-11-08
DOI
https://doi.org/10.5281/zenodo.24069930
Primary Topic
Markov Chains and Monte Carlo Methods
Type
preprint
Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
NOV
preprint

The relaxation time does not control the normal approximation of stationary additive functionals

Yitzchak Shmalo
Zenodo (CERN European Organization for Nuclear Research)
Markov Chains and Monte Carlo Methods
preprint

The relaxation time does not control the normal approximation of stationary additive functionals

Yitzchak Shmalo
preprint en

Abstract

Let $X$ be a finite irreducible reversible Markov chain in continuous time with relaxation time $\tau_2$, started from its stationary distribution, and let $g$ be a function on its states with mean $0$ and variance $1$ under that distribution. Aldous and Fill asked whether the Kolmogorov distance between $\int_0^tg(X_u)\,du/(\sigma t^{1/2})$, where $\sigma^2$ is the asymptotic variance rate, and the standard normal law is bounded by a function of $\max|g|$ and $t/\tau_2$ alone that tends to $0$ as $t/\tau_2\to\infty$. It is not. For every $b\ge1$ and $s\ge2b$ there are a chain on four states with $\tau_2=1$ and a function $g$ of mean $0$ and variance $1$ with $\max|g|=b$ such that $\int_0^sg(X_u)\,du\le0$ with probability at least $1-4/s$, so at $t=s$ the distance is at least $1/2-4/s$ whatever positive constant the integral is divided by.

Zenodo (CERN European Organization for Nuclear Research)
Hebrew University of Jerusalem (IL)
Markov Chains and Monte Carlo Methods
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.

Laika access coming soon