PreprintCC BY 4.0arXiv
The Keevash--Mubayi simplex-cluster conjecture
Abstract
A d-simplex-cluster is a collection of d+1 distinct k-element sets with empty total intersection, nonempty intersection for every d members, and union of size at most 2k. We prove the simplex-cluster conjecture of Keevash and Mubayi, a common strengthening of the Erdős--Chvátal simplex conjecture and Mubayi's cluster conjecture. More precisely, for integers k>d≥2 and n≥ k(d+1)/d, every family of k-element subsets of an n-element set containing no d-simplex-cluster has at most binomn−1k−1 members. Equality holds if and only if the family consists of all k-element subsets containing a fixed point.
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BibTeX
@misc{wu2026keevashmubayi,
title = {{The Keevash--Mubayi simplex-cluster conjecture}},
author = {Yongjiang Wu and Lihua Feng},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.08567},
eprint = {2610.08567},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.08567},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - The Keevash--Mubayi simplex-cluster conjecture
AU - Yongjiang Wu
AU - Lihua Feng
PY - 2026
DA - 2026/10/06
PB - arXiv
DO - 10.48550/arxiv.2610.08567
UR - https://arxiv.org/abs/2610.08567
AB - A d-simplex-cluster is a collection of d+1 distinct k-element sets with empty total intersection, nonempty intersection for every d members, and union of size at most 2k. We prove the simplex-cluster conjecture of Keevash and Mubayi, a common strengthening of the Erdős--Chvátal simplex conjecture and Mubayi's cluster conjecture. More precisely, for integers k>d≥2 and n≥ k(d+1)/d, every family of k-element subsets of an n-element set containing no d-simplex-cluster has at most binomn−1k−1 members. Equality holds if and only if the family consists of all k-element subsets containing a fixed point.
ER -