Counting H-free orientations of graphs


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Date

2023-01

Publication Type

Journal Article

ETH Bibliography

yes

Citations

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Abstract

In 1974, Erdos posed the following problem. Given an oriented graph ˝ H, determine or estimate the maximum possible number of H-free orientations of an n-vertex graph. When H is a tournament, the answer was determined precisely for sufficiently large n by Alon and Yuster. In general, when the underlying undirected graph of H contains a cycle, one can obtain accurate bounds by combining an observation of Kozma and Moran with celebrated results on the number of F-free graphs. As the main contribution of the paper, we resolve all remaining cases in an asymptotic sense, thereby giving a rather complete answer to Erdos’s ˝ question. Moreover, we determine the answer exactly when H is an odd cycle and n is sufficiently large, answering a question of Araújo, Botler and Mota.

Publication status

published

Editor

Book title

Volume

174 (1)

Pages / Article No.

79 - 95

Publisher

Cambridge University Press

Event

Edition / version

Methods

Software

Geographic location

Date collected

Date created

Subject

Organisational unit

03993 - Sudakov, Benjamin / Sudakov, Benjamin check_circle

Notes

Funding

196965 - Problems in Extremal and Probabilistic Combinatorics (SNF)
20-1 FEL-35 - Problems in Extremal Combinatorics (ETHZ)

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