Cross-intersection theorems for uniform partitions of finite sets

Fuente: arXiv
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Auteurs principaux: Yao, Tian, Cao, Mengyu, Zhang, Haixiang
Format: Preprint
Publié: 2025
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author Yao, Tian
Cao, Mengyu
Zhang, Haixiang
author_facet Yao, Tian
Cao, Mengyu
Zhang, Haixiang
contents A set partition is $c$-uniform if every block has size $c$. Two families of $c$-uniform partitions of a finite set are said to be cross $t$-intersecting if two partitions from different families share at least $t$ blocks. In this paper, we establish some product-type extremal results for such cross $t$-intersecting families. Our results yield an Erdős-Ko-Rado theorem and a Hilton-Milner theorem for uniform set partitions. Additionally, cross $t$-intersecting families with the maximum sum of their sizes are also characterized.
format Preprint
id arxiv_https___arxiv_org_abs_2509_17188
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Cross-intersection theorems for uniform partitions of finite sets
Yao, Tian
Cao, Mengyu
Zhang, Haixiang
Combinatorics
05D05
A set partition is $c$-uniform if every block has size $c$. Two families of $c$-uniform partitions of a finite set are said to be cross $t$-intersecting if two partitions from different families share at least $t$ blocks. In this paper, we establish some product-type extremal results for such cross $t$-intersecting families. Our results yield an Erdős-Ko-Rado theorem and a Hilton-Milner theorem for uniform set partitions. Additionally, cross $t$-intersecting families with the maximum sum of their sizes are also characterized.
title Cross-intersection theorems for uniform partitions of finite sets
topic Combinatorics
05D05
url https://arxiv.org/abs/2509.17188