Online Matching and Contention Resolution for Edge Arrivals with Vanishing Probabilities

Fuente: arXiv
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Autori principali: Ma, Will, MacRury, Calum, Nuti, Pranav
Natura: Preprint
Pubblicazione: 2024
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author Ma, Will
MacRury, Calum
Nuti, Pranav
author_facet Ma, Will
MacRury, Calum
Nuti, Pranav
contents We study the performance of sequential contention resolution and matching algorithms on random graphs with vanishing edge probabilities. When the edges of the graph are processed in an adversarially-chosen order, we derive a new OCRS that is $0.382$-selectable, attaining the "independence benchmark" from the literature under the vanishing edge probabilities assumption. Complementary to this positive result, we show that no OCRS can be more than $0.390$-selectable, significantly improving upon the upper bound of $0.428$ from the literature. We also derive negative results that are specialized to bipartite graphs or subfamilies of OCRS's. Meanwhile, when the edges of the graph are processed in a uniformly random order, we show that the simple greedy contention resolution scheme which accepts all active and feasible edges is $1/2$-selectable. This result is tight due to a known upper bound. Finally, when the algorithm can choose the processing order, we show that a slight tweak to the random order -- give each vertex a random priority and process edges in lexicographic order -- results in a strictly better contention resolution scheme that is $1-\ln(2-1/e)\approx0.510$-selectable. Our positive results also apply to online matching on $1$-uniform random graphs with vanishing (non-identical) edge probabilities, extending and unifying some results from the random graphs literature.
format Preprint
id arxiv_https___arxiv_org_abs_2406_14506
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Online Matching and Contention Resolution for Edge Arrivals with Vanishing Probabilities
Ma, Will
MacRury, Calum
Nuti, Pranav
Data Structures and Algorithms
Discrete Mathematics
Combinatorics
F.2.2; G.2.2
We study the performance of sequential contention resolution and matching algorithms on random graphs with vanishing edge probabilities. When the edges of the graph are processed in an adversarially-chosen order, we derive a new OCRS that is $0.382$-selectable, attaining the "independence benchmark" from the literature under the vanishing edge probabilities assumption. Complementary to this positive result, we show that no OCRS can be more than $0.390$-selectable, significantly improving upon the upper bound of $0.428$ from the literature. We also derive negative results that are specialized to bipartite graphs or subfamilies of OCRS's. Meanwhile, when the edges of the graph are processed in a uniformly random order, we show that the simple greedy contention resolution scheme which accepts all active and feasible edges is $1/2$-selectable. This result is tight due to a known upper bound. Finally, when the algorithm can choose the processing order, we show that a slight tweak to the random order -- give each vertex a random priority and process edges in lexicographic order -- results in a strictly better contention resolution scheme that is $1-\ln(2-1/e)\approx0.510$-selectable. Our positive results also apply to online matching on $1$-uniform random graphs with vanishing (non-identical) edge probabilities, extending and unifying some results from the random graphs literature.
title Online Matching and Contention Resolution for Edge Arrivals with Vanishing Probabilities
topic Data Structures and Algorithms
Discrete Mathematics
Combinatorics
F.2.2; G.2.2
url https://arxiv.org/abs/2406.14506