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Bibliographic Details
Main Authors: Frankl, Peter, Kupavskii, Andrey
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2408.08221
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author Frankl, Peter
Kupavskii, Andrey
author_facet Frankl, Peter
Kupavskii, Andrey
contents Let us consider a collection $\mathcal G$ of codewords of length $n$ over an alphabet of size $s$. Let $t_1,\ldots, t_s$ be nonnegative integers. What is the maximum of $|\mathcal G|$ subject to the condition that any two codewords should have at least $t_i$ positions where both have letter $i$ ($1\le i\le s$). In the case $s=2$ it is a longstanding open question. Quite surprisingly, we obtain an almost complete answer for $s\ge 3$. The main tool is a correlation inequality.
format Preprint
id arxiv_https___arxiv_org_abs_2408_08221
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Intersection problems and a correlation inequality for integer sequences
Frankl, Peter
Kupavskii, Andrey
Combinatorics
Let us consider a collection $\mathcal G$ of codewords of length $n$ over an alphabet of size $s$. Let $t_1,\ldots, t_s$ be nonnegative integers. What is the maximum of $|\mathcal G|$ subject to the condition that any two codewords should have at least $t_i$ positions where both have letter $i$ ($1\le i\le s$). In the case $s=2$ it is a longstanding open question. Quite surprisingly, we obtain an almost complete answer for $s\ge 3$. The main tool is a correlation inequality.
title Intersection problems and a correlation inequality for integer sequences
topic Combinatorics
url https://arxiv.org/abs/2408.08221