English

Markov chains arising from biased random derangements

Probability 2022-11-28 v1

Abstract

We explore the cycle types of a class of biased random derangements, described as a random game played by some children labeled 1,,n1,\cdots,n. Children join the game one by one, in a random order, and randomly form some circles of size at least 22, so that no child is left alone. The game gives rise to the cyclic decomposition of a random derangement, inducing an exchangeable random partition. The rate at which the circles are closed varies in time, and at each time tt, depends on the number of individuals who have not played until t. A {0,1}\{0,1\}-valued Markov chain Xn X^n records the cycle type of the corresponding random derangement in that any 11 represents a hand-grasping event that closes a circle. Using this, we study the cycle counts and sizes of the random derangements and their asymptotic behavior. We approximate the total variation distance between the reversed chain of XnX^n and its weak limit XX^\infty, as nn\to\infty. We establish conditional (and push-forward) relations between XnX^n and a generalization of the Feller coupling, given that no 1111-pattern (11-cycle) appears in the latter. We extend these relations to XX^\infty and apply them to investigate some asymptotic behaviors of XnX^n.

Keywords

Cite

@article{arxiv.2211.13831,
  title  = {Markov chains arising from biased random derangements},
  author = {Poly H. da Silva and Arash Jamshidpey and Simon Tavaré},
  journal= {arXiv preprint arXiv:2211.13831},
  year   = {2022}
}
R2 v1 2026-06-28T07:12:10.114Z