Title
Matrix Concentration for Expander Walks.
Abstract
We prove a Chernoff-type bound for sums of matrix-valued random variables sampled via a random walk on an expander, confirming a conjecture of Wigderson and Xiao up to logarithmic factors in the deviation parameter. Our proof is based on a recent multi-matrix extension of the Golden-Thompson inequality due to Sutter et al. cite{Sutter2017}, as well as an adaptation of an argument for the scalar case due to Healy cite{healy08}. Secondarily, we also provide a generic reduction showing that any concentration inequality for vector-valued martingales implies a concentration inequality for the corresponding expander walk, with a weakening of parameters roughly proportional to the squared mixing time.
Year
Venue
Field
2017
arXiv: Probability
Discrete mathematics,Combinatorics,Martingale (probability theory),Random variable,Square (algebra),Random walk,Matrix (mathematics),Logarithm,Concentration inequality,Conjecture,Mathematics
DocType
Volume
Citations 
Journal
abs/1704.03864
1
PageRank 
References 
Authors
0.35
5
2
Name
Order
Citations
PageRank
Ankit Garg112516.19
Nikhil Srivastava226216.09