Randomized Greedy Online Edge Coloring Succeeds for Dense and Randomly-Ordered Graphs

Fuente: arXiv
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Main Authors: Dudeja, Aditi, Goswami, Rashmika, Saks, Michael
Format: Preprint
Published: 2024
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author Dudeja, Aditi
Goswami, Rashmika
Saks, Michael
author_facet Dudeja, Aditi
Goswami, Rashmika
Saks, Michael
contents Vizing's theorem states that any graph of maximum degree $Δ$ can be properly edge colored with at most $Δ+1$ colors. In the online setting, it has been a matter of interest to find an algorithm that can properly edge color any graph on $n$ vertices with maximum degree $Δ= ω(\log n)$ using at most $(1+o(1))Δ$ colors. Here we study the naïve random greedy algorithm, which simply chooses a legal color uniformly at random for each edge upon arrival. We show that this algorithm can $(1+ε)Δ$-color the graph for arbitrary $ε$ in two contexts: first, if the edges arrive in a uniformly random order, and second, if the edges arrive in an adversarial order but the graph is sufficiently dense, i.e., $n = O(Δ)$. Prior to this work, the random greedy algorithm was only known to succeed in trees. Our second result is applicable even when the adversary is adaptive, and therefore implies the existence of a deterministic edge coloring algorithm which $(1+ε)Δ$ edge colors a dense graph. Prior to this, the best known deterministic algorithm for this problem was the simple greedy algorithm which utilized $2Δ-1$ colors.
format Preprint
id arxiv_https___arxiv_org_abs_2406_13000
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Randomized Greedy Online Edge Coloring Succeeds for Dense and Randomly-Ordered Graphs
Dudeja, Aditi
Goswami, Rashmika
Saks, Michael
Data Structures and Algorithms
Discrete Mathematics
Combinatorics
Vizing's theorem states that any graph of maximum degree $Δ$ can be properly edge colored with at most $Δ+1$ colors. In the online setting, it has been a matter of interest to find an algorithm that can properly edge color any graph on $n$ vertices with maximum degree $Δ= ω(\log n)$ using at most $(1+o(1))Δ$ colors. Here we study the naïve random greedy algorithm, which simply chooses a legal color uniformly at random for each edge upon arrival. We show that this algorithm can $(1+ε)Δ$-color the graph for arbitrary $ε$ in two contexts: first, if the edges arrive in a uniformly random order, and second, if the edges arrive in an adversarial order but the graph is sufficiently dense, i.e., $n = O(Δ)$. Prior to this work, the random greedy algorithm was only known to succeed in trees. Our second result is applicable even when the adversary is adaptive, and therefore implies the existence of a deterministic edge coloring algorithm which $(1+ε)Δ$ edge colors a dense graph. Prior to this, the best known deterministic algorithm for this problem was the simple greedy algorithm which utilized $2Δ-1$ colors.
title Randomized Greedy Online Edge Coloring Succeeds for Dense and Randomly-Ordered Graphs
topic Data Structures and Algorithms
Discrete Mathematics
Combinatorics
url https://arxiv.org/abs/2406.13000