Title
A Fixed Point Theorem for Iterative Random Contraction Operators over Banach Spaces.
Abstract
Consider a contraction operator $T$ over a Banach space $mathcal X$ with a fixed point $x^star$. Assume that one can approximate the operator $T$ by a random operator $hat T^N$ using $Ninmathbb{N}$ independent and identically distributed samples of a random variable. Consider the sequence $(hat X^N_k)_{kinmathbb{N}}$, which is generated by $hat X^N_{k+1} = hat T^N(hat X^N_k)$ and is a random sequence. In this paper, we prove that under certain conditions on the random operator, (i) the distribution of $hat X^N_k$ converges to a unit mass over $x^star$ as $k$ and $N$ goes to infinity, and (ii) the probability that $hat X^N_k$ is far from $x^star$ as $k$ goes to infinity can be made arbitrarily small by an appropriate choice of $N$. We also find a lower bound on the probability that $hat X^N_k$ is far from $x^star$ as $krightarrow infty$. We apply the result to study probabilistic convergence of certain randomized optimization and value iteration algorithms.
Year
Venue
Field
2018
arXiv: Probability
Combinatorics,Random variable,Upper and lower bounds,Infinity,Banach space,Operator (computer programming),Independent and identically distributed random variables,Fixed point,Mathematics,Fixed-point theorem
DocType
Volume
Citations 
Journal
abs/1804.01195
0
PageRank 
References 
Authors
0.34
0
3
Name
Order
Citations
PageRank
Abhishek Gupta11410.61
Rahul Jain278471.51
Peter W. Glynn31527293.76