PreprintCC BY 4.0arXiv
On decomposition thresholds for odd cycles
Abstract
We determine the asymptotic minimum-degree threshold for decompositions into cycles of a fixed odd length. We prove that, for each odd integer ℓ≥3, every eps>0 and sufficiently large n, every n-vertex Cℓ-divisible graph G with minimum degree δ(G)≥ (ℓ/(2ℓ−2)+eps)n has a Cℓ-decomposition, where Cℓ denotes the cycle of length ℓ. This settles the remaining cases ℓ=5,7,…,71 and completes the determination of the thresholds for all odd cycles. Our main ingredient is a sharp fractional decomposition theorem for weighted triangles: for every real a≥ 1,every n-vertex graph G with δ(G)≥ (1/2+1/(2(a+1)))n admits a fractional decomposition into triangles with edge weights a,1,1.
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BibTeX
@misc{hou2026decomposition,
title = {{On decomposition thresholds for odd cycles}},
author = {Jianfeng Hou and Caiyun Hu and Hezhi Wang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.23471},
eprint = {2610.23471},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.23471},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - On decomposition thresholds for odd cycles
AU - Jianfeng Hou
AU - Caiyun Hu
AU - Hezhi Wang
PY - 2026
DA - 2026/10/22
PB - arXiv
DO - 10.48550/arxiv.2610.23471
UR - https://arxiv.org/abs/2610.23471
AB - We determine the asymptotic minimum-degree threshold for decompositions into cycles of a fixed odd length. We prove that, for each odd integer ℓ≥3, every eps>0 and sufficiently large n, every n-vertex C_ℓ-divisible graph G with minimum degree δ(G)≥ (ℓ/(2ℓ−2)+eps)n has a C_ℓ-decomposition, where C_ℓ denotes the cycle of length ℓ. This settles the remaining cases ℓ=5,7,…,71 and completes the determination of the thresholds for all odd cycles. Our main ingredient is a sharp fractional decomposition theorem for weighted triangles: for every real a≥ 1,every n-vertex graph G with δ(G)≥ (1/2+1/(2(a+1)))n admits a fractional decomposition into triangles with edge weights a,1,1.
ER -