Mixing of fast random walks on dynamic random permutations

Probability Theory and Related Fields, vol. 194, pp. 779–831

Abstract

We analyse the mixing profile of a random walk on a dynamic random permutation, focusing on the regime where the walk evolves much faster than the permutation. Two types of dynamics generated by random transpositions are considered: one allows for coagulation of permutation cycles only, the other allows for both coagulation and fragmentation. We show that for both types, after scaling time by the length of the permutation and letting this length tend to infinity, the total variation distance between the current distribution and the uniform distribution converges to a limit process that drops down in a single jump. This jump is similar to a one-sided cut-off, occurs after a random time whose law we identify, and goes from the value 1 to a value that is a strictly decreasing and deterministic function of the time of the jump, related to the size of the largest component in Erdős-Rényi random graphs. After the jump, the total variation distance follows this function down to 0.

Authors 4

1. Luca Avena

   University of Florence

   Affiliation as printed

   Dipartimento di Matematica e Informatica 'Ulisse Dini', Università degli Studi di Firenze, Florence, Italy

2. Remco van der Hofstad

   Eindhoven University of Technology

   Affiliation as printed

   Department of Mathematics and Computer Science, Eindhoven University of Technology, Eindhoven, The Netherlands

3. Frank den Hollander Aachen Mathematical Institute

   Leiden University

   Affiliation as printed

   Mathematical Institute, Leiden University, Leiden, The Netherlands

4. Oliver Nagy corresponding Aachen Mathematical Institute

   Leiden University

   Affiliation as printed

   Mathematical Institute, Leiden University, Leiden, The Netherlands