Open Access
2024 Limits of Mallows trees
Benoît Corsini
Author Affiliations +
Electron. J. Probab. 29: 1-44 (2024). DOI: 10.1214/24-EJP1167

Abstract

This article studies the limit of binary search trees drawn from Mallows permutations under various topologies. The main result, pertaining to the standard local topology for graphs, requires the introduction of a generalization of binary search trees to two-sided infinite sequences, referred to as redwood trees. We then show that the almost-sure local limit of finite Mallows trees is the redwood tree drawn from the two-sided infinite Mallows permutation, thus corresponding to swapping the local limit and the binary search tree structure.

Building off this result, we study various other natural topologies: the rooted topology of the local structure around the root, the Gromov-Hausdorff-Prokhorov topology of the tree seen as a metric space, the pointwise convergence of the contour function, and the subtree size topology of the ratio of nodes split between left and right subtrees. The limit of Mallows trees under these four topologies combined with the case of the local topology allow us to draw a global picture of what large Mallows trees look like from different perspective and further strengthen the relation between finite and infinite Mallows permutations.

Funding Statement

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 101034253.

Acknowledgments

The author would like to thank Michał Kotowski for mentioning the case of the contour function, which naturally fits within the framework of this article, and an anonymous reviewer who helped in making the results clearer and stronger.

Citation

Download Citation

Benoît Corsini. "Limits of Mallows trees." Electron. J. Probab. 29 1 - 44, 2024. https://doi.org/10.1214/24-EJP1167

Information

Received: 13 January 2024; Accepted: 30 June 2024; Published: 2024
First available in Project Euclid: 30 July 2024

Digital Object Identifier: 10.1214/24-EJP1167

Subjects:
Primary: 05A05 , 05C05 , 60C05 , 60F15

Keywords: Binary search trees , Local limits , Mallows permutations , Mallows trees , Random trees

Vol.29 • 2024
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