Home > Research > Publications & Outputs > The power of two choices for random walks

Links

Text available via DOI:

View graph of relations

The power of two choices for random walks

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Published
Close
<mark>Journal publication date</mark>1/01/2022
<mark>Journal</mark>Combinatorics, Probability and Computing
Issue number1
Volume31
Number of pages28
Pages (from-to)73-100
Publication StatusPublished
Early online date28/05/21
<mark>Original language</mark>English

Abstract

We apply the power-of-two-choices paradigm to a random walk on a graph: rather than moving to a uniform random neighbour at each step, a controller is allowed to choose from two independent uniform random neighbours. We prove that this allows the controller to significantly accelerate the hitting and cover times in several natural graph classes. In particular, we show that the cover time becomes linear in the number n of vertices on discrete tori and bounded degree trees, of order O(n log log n) on bounded degree expanders, and of order O(n(log log n) 2) on the Erdős-Rényi random graph in a certain sparsely connected regime.We also consider the algorithmic question of computing an optimal strategy and prove a dichotomy in efficiency between computing strategies for hitting and cover times.