A Short Proof and Generalization of the Rainbow Cycle Theorem and Improved Bounds for Binary Even-Query LCCs
Abstract
A \emph{rainbow cycle} in a list-edge-colored graph is a cycle where no color appears more than once. We give a short and simple proof of a result of [ABSZZ] showing that a properly edge-colored n-vertex graph with average degree Ω(log nloglog n) always contains a rainbow cycle, and generalize it to weighted graphs with edges list colored with list size at most ℓ and where the total weight of all edges containing a given color i incident to a vertex is at most Δ, showing that Ωℓ(Δlog nloglog n) average degree guarantees a rainbow cycle. Using the reduction of [AG26] and the new generalized rainbow cycle theorem, we prove that for r≥ 3, every binary linear r-query locally correctable code E:𝔽2k→ 𝔽2n satisfies k≤ Õ(n1−2/(r−1)) by showing a rainbow analogue of the odd r-LDC lower bounds of [BHKL25,JM25], closing the gap between the best known lower bounds for odd- and even-query binary linear r-LCCs.
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BibTeX
@misc{lin2026short,
title = {{A Short Proof and Generalization of the Rainbow Cycle Theorem and Improved Bounds for Binary Even-Query LCCs}},
author = {Andrew D. Lin},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.05034},
eprint = {2611.05034},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.05034},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - A Short Proof and Generalization of the Rainbow Cycle Theorem and Improved Bounds for Binary Even-Query LCCs
AU - Andrew D. Lin
PY - 2026
DA - 2026/11/03
PB - arXiv
DO - 10.48550/arxiv.2611.05034
UR - https://arxiv.org/abs/2611.05034
AB - A \emph{rainbow cycle} in a list-edge-colored graph is a cycle where no color appears more than once. We give a short and simple proof of a result of [ABSZZ] showing that a properly edge-colored n-vertex graph with average degree Ω(log nloglog n) always contains a rainbow cycle, and generalize it to weighted graphs with edges list colored with list size at most ℓ and where the total weight of all edges containing a given color i incident to a vertex is at most Δ, showing that Ω_ℓ(Δlog nloglog n) average degree guarantees a rainbow cycle. Using the reduction of [AG26] and the new generalized rainbow cycle theorem, we prove that for r≥ 3, every binary linear r-query locally correctable code E:𝔽_2^k→ 𝔽_2^n satisfies k≤ Õ(n^1−2/(r−1)) by showing a rainbow analogue of the odd r-LDC lower bounds of [BHKL25,JM25], closing the gap between the best known lower bounds for odd- and even-query binary linear r-LCCs.
ER -