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Bibliographic Details
Main Authors: Ray, Gourab, Sen, Arnab
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2401.13238
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author Ray, Gourab
Sen, Arnab
author_facet Ray, Gourab
Sen, Arnab
contents We study the minimal spanning arborescence which is the directed analogue of the minimal spanning tree, with a particular focus on its infinite volume limit and its geometric properties. We prove that in a certain large class of transient trees, the infinite volume limit exists almost surely. We also prove that for nonamenable, unimodular graphs, the limit is almost surely one-ended assuming a certain sufficient condition that guarantees the existence of the limit. This object cannot be studied using well-known algorithms, such as Kruskal's or Prim's algorithm, to sample the minimal spanning tree which has been instrumental in getting analogous results about them (Lyons, Peres, and Schramm). Instead, we use a recursive algorithm due to Chu, Liu, Edmonds, and Bock, which leads to a novel stochastic process which we call the \emph{loop contracting random walk}. This is similar to the well-known and widely studied loop erased random walk, except instead of erasing loops we contract them. The full algorithm bears similarities with the celebrated Wilson's algorithm to generate uniform spanning trees and can be seen as a certain limit of the original Wilson's algorithm.
format Preprint
id arxiv_https___arxiv_org_abs_2401_13238
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Minimal spanning arborescence
Ray, Gourab
Sen, Arnab
Probability
Data Structures and Algorithms
Combinatorics
We study the minimal spanning arborescence which is the directed analogue of the minimal spanning tree, with a particular focus on its infinite volume limit and its geometric properties. We prove that in a certain large class of transient trees, the infinite volume limit exists almost surely. We also prove that for nonamenable, unimodular graphs, the limit is almost surely one-ended assuming a certain sufficient condition that guarantees the existence of the limit. This object cannot be studied using well-known algorithms, such as Kruskal's or Prim's algorithm, to sample the minimal spanning tree which has been instrumental in getting analogous results about them (Lyons, Peres, and Schramm). Instead, we use a recursive algorithm due to Chu, Liu, Edmonds, and Bock, which leads to a novel stochastic process which we call the \emph{loop contracting random walk}. This is similar to the well-known and widely studied loop erased random walk, except instead of erasing loops we contract them. The full algorithm bears similarities with the celebrated Wilson's algorithm to generate uniform spanning trees and can be seen as a certain limit of the original Wilson's algorithm.
title Minimal spanning arborescence
topic Probability
Data Structures and Algorithms
Combinatorics
url https://arxiv.org/abs/2401.13238