Nonexpansive Markov Operators and Random Function Iterations for Stochastic Fixed Point Problems

Fuente: arXiv
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Main Authors: Hermer, Neal, Luke, D. Russell, Sturm, Anja
Format: Preprint
Published: 2022
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author Hermer, Neal
Luke, D. Russell
Sturm, Anja
author_facet Hermer, Neal
Luke, D. Russell
Sturm, Anja
contents We study the convergence of random function iterations for finding an invariant measure of the corresponding Markov operator. We call the problem of finding such an invariant measure the stochastic fixed point problem. This generalizes earlier work studying the stochastic feasibility problem, namely, to find points that are, with probability 1, fixed points of the random functions. When no such points exist, the stochastic feasibility problem is called inconsistent, but still under certain assumptions, the more general stochastic fixed point problem has a solution and the random function iterations converge to an invariant measure for the corresponding Markov operator. We show how common structures in deterministic fixed point theory can be exploited to establish existence of invariant measures and convergence in distribution of the Markov chain. This framework specializes to many applications of current interest including, for instance, stochastic algorithms for large-scale distributed computation, and deterministic iterative procedures with computational error. The theory developed in this study provides a solid basis for describing the convergence of simple computational methods without the assumption of infinite precision arithmetic or vanishing computational errors.
format Preprint
id arxiv_https___arxiv_org_abs_2205_15897
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Nonexpansive Markov Operators and Random Function Iterations for Stochastic Fixed Point Problems
Hermer, Neal
Luke, D. Russell
Sturm, Anja
Optimization and Control
Probability
60J05, 46N10, 46N30, 65C40, 49J55
We study the convergence of random function iterations for finding an invariant measure of the corresponding Markov operator. We call the problem of finding such an invariant measure the stochastic fixed point problem. This generalizes earlier work studying the stochastic feasibility problem, namely, to find points that are, with probability 1, fixed points of the random functions. When no such points exist, the stochastic feasibility problem is called inconsistent, but still under certain assumptions, the more general stochastic fixed point problem has a solution and the random function iterations converge to an invariant measure for the corresponding Markov operator. We show how common structures in deterministic fixed point theory can be exploited to establish existence of invariant measures and convergence in distribution of the Markov chain. This framework specializes to many applications of current interest including, for instance, stochastic algorithms for large-scale distributed computation, and deterministic iterative procedures with computational error. The theory developed in this study provides a solid basis for describing the convergence of simple computational methods without the assumption of infinite precision arithmetic or vanishing computational errors.
title Nonexpansive Markov Operators and Random Function Iterations for Stochastic Fixed Point Problems
topic Optimization and Control
Probability
60J05, 46N10, 46N30, 65C40, 49J55
url https://arxiv.org/abs/2205.15897