Multiparty equality in the local broadcast model

Fuente: arXiv
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Main Authors: Esperet, Louis, Raymond, Jean-Florent
Format: Preprint
Published: 2025
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author Esperet, Louis
Raymond, Jean-Florent
author_facet Esperet, Louis
Raymond, Jean-Florent
contents In this paper we consider the multiparty equality problem in graphs, where every vertex of a graph $G$ is given an input, and the goal of the vertices is to decide whether all inputs are equal. We study this problem in the local broadcast model, where a message sent by a vertex is received by all its neighbors and the total cost of a protocol is the sum of the lengths of the messages sent by the vertices. This setting was studied by Khan and Vaidya, who gave in 2021 a protocol achieving a 4-approximation in the general case. We study this multiparty communication problem through the lens of network topology. We design a new protocol for 2-connected graphs, whose efficiency relies on the notion of total vertex cover in graph theory. This protocol outperforms the aforementioned 4-approximation in a number of cases. To demonstrate its applicability, we apply it to obtain optimal or asymptotically optimal protocols for several natural network topologies such as cycles, hypercubes, and grids. On the way we also provide new bounds of independent interest on the size of total vertex covers in regular graphs.
format Preprint
id arxiv_https___arxiv_org_abs_2510_09143
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Multiparty equality in the local broadcast model
Esperet, Louis
Raymond, Jean-Florent
Combinatorics
Computational Complexity
Distributed, Parallel, and Cluster Computing
In this paper we consider the multiparty equality problem in graphs, where every vertex of a graph $G$ is given an input, and the goal of the vertices is to decide whether all inputs are equal. We study this problem in the local broadcast model, where a message sent by a vertex is received by all its neighbors and the total cost of a protocol is the sum of the lengths of the messages sent by the vertices. This setting was studied by Khan and Vaidya, who gave in 2021 a protocol achieving a 4-approximation in the general case. We study this multiparty communication problem through the lens of network topology. We design a new protocol for 2-connected graphs, whose efficiency relies on the notion of total vertex cover in graph theory. This protocol outperforms the aforementioned 4-approximation in a number of cases. To demonstrate its applicability, we apply it to obtain optimal or asymptotically optimal protocols for several natural network topologies such as cycles, hypercubes, and grids. On the way we also provide new bounds of independent interest on the size of total vertex covers in regular graphs.
title Multiparty equality in the local broadcast model
topic Combinatorics
Computational Complexity
Distributed, Parallel, and Cluster Computing
url https://arxiv.org/abs/2510.09143