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Dimension is a standard and well-studied measure of complexity of posets. Recent research has provided many new upper bounds on the dimension for various structurally restricted classes of posets. Bounded dimension gives a succinct…

Combinatorics · Mathematics 2017-05-26 William T. Trotter , Bartosz Walczak

How large can a family \cal A \subset \cal P [n] be if it does not contain A,B with |A\setminus B| = 1? Our aim in this paper is to show that any such family has size at most \frac{2+o(1)}{n} \binom {n}{\lfloor n/2\rfloor }. This is tight…

Combinatorics · Mathematics 2013-11-25 Imre Leader , Eoin Long

Fix a density d in (0,1], and let F_p^n be a finite field, where we think of p fixed and n tending to infinity. Let S be any subset of F_p^n having the minimal number of three-term progressions, subject to the constraint |S| is at least…

Number Theory · Mathematics 2007-05-23 Ernie Croot

The partition problem is a well-known basic NP-complete problem. We mainly consider the optimization version of it in this paper. The problem has been investigated from various perspectives for a long time and can be solved efficiently in…

Discrete Mathematics · Computer Science 2024-05-10 Susumu Kubo

We study two new parameters for finite posets motivated by the problem of efficiently determining the set of successors of a given element. A plane map of a poset $P=(X,\leq)$ is an injective mapping of $X$ into the Cartesian plane…

Combinatorics · Mathematics 2026-05-21 Stefan Felsner , Jędrzej Hodor , Giacomo Ortali , Alexander Wolff

Given a finite poset P, we consider the largest size La(n,P) of a family of subsets of $[n]:=\{1,...,n\}$ that contains no subposet P. This problem has been studied intensively in recent years, and it is conjectured that $\pi(P):=…

Combinatorics · Mathematics 2011-09-07 Jerrold R. Griggs , Wei-Tian Li , Linyuan Lu

The linear extension diameter of a finite poset P is the maximum distance between a pair of linear extensions of P, where the distance between two linear extensions is the number of pairs of elements of P appearing in different orders in…

Combinatorics · Mathematics 2009-07-13 Stefan Felsner , Mareike Massow

Over the past 10 years, there has been considerable interest in exploring questions connecting dimension for posets with graph theoretic properties of their cover graphs and order diagrams, especially with the concepts of planarity and…

Combinatorics · Mathematics 2023-04-18 Jędrzej Hodor , William T. Trotter

For a positive integer $d$, a set of points in $d$-dimensional Euclidean space is called almost-equidistant if for any three points from the set, some two are at unit distance. Let $f(d)$ denote the largest size of an almost-equidistant set…

Metric Geometry · Mathematics 2020-02-25 Martin Balko , Attila Pór , Manfred Scheucher , Konrad Swanepoel , Pavel Valtr

Let $F$ be a family of subsets of $\{1,\ldots,n\}$. We say that $F$ is $P$-free if the inclusion order on $F$ does not contain $P$ as an induced subposet. The \emph{Tur\'an function} of $P$, denoted $\pi^*(n,P)$, is the maximum size of a…

Combinatorics · Mathematics 2014-08-05 Linyuan Lu , Kevin G. Milans

Let us fix a prime $p$. The Erd\H{o}s-Ginzburg-Ziv problem asks for the minimum integer $s$ such that any collection of $s$ points in the lattice $\mathbb{Z}^n$ contains $p$ points whose centroid is also a lattice point in $\mathbb{Z}^n$.…

Combinatorics · Mathematics 2020-06-30 Lisa Sauermann

For any positive integers $n\ge d+1\ge 3$, what is the maximum size of a $(d+1)$-uniform set system in $[n]$ with VC-dimension at most $d$? In 1984, Frankl and Pach initiated the study of this fundamental problem and provided an upper bound…

Combinatorics · Mathematics 2025-06-06 Gennian Ge , Zixiang Xu , Chi Hoi Yip , Shengtong Zhang , Xiaochen Zhao

Set $[n]=\{1, 2, \ldots , n\}$. The hypergrid $[t]^n$ is the collection of functions $f: \ [n]\rightarrow [t]$. We equip it with the natural partial order by letting $f\leq g$ whenever $f(x)\leq g(x)$ holds for all $x\in [n]$. Given a poset…

Combinatorics · Mathematics 2026-04-15 R. Altar Ciceksiz , Victor Falgas-Ravry , Sabrina Lato , Maryam Sharifzadeh

Given partially ordered sets (posets) $(P, \leq_P)$ and $(P', \leq_{P'})$, we say that $P'$ contains a copy of $P$ if for some injective function $f\colon P\rightarrow P'$ and for any $A, B\in P$, $A\leq _P B$ if and only if $f(A)\leq_{P'}…

Combinatorics · Mathematics 2023-07-06 Maria Axenovich , Christian Winter

Felsner and Reuter introduced the linear extension diameter of a partially ordered set $\mathbf{P}$, denoted $\mbox{led}(\mathbf{P})$, as the maximum distance between two linear extensions of $\mathbf{P}$, where distance is defined to be…

Combinatorics · Mathematics 2015-07-07 Graham Brightwell , Mitchel T. Keller

A set $S$ of permutations is forcing if for any sequence $\{\Pi_i\}_{i \in \mathbb{N}}$ of permutations where the density $d(\pi,\Pi_i)$ converges to $\frac{1}{|\pi|!}$ for every permutation $\pi \in S$, it holds that $\{\Pi_i\}_{i \in…

Combinatorics · Mathematics 2021-10-15 Martin Kurecka

The original notion of dimension for posets is due to Dushnik and Miller and has been studied extensively in the literature. Quite recently, there has been considerable interest in two variations of dimension known as Boolean dimension and…

Combinatorics · Mathematics 2019-06-25 Fidel Barrera-Cruz , Thomas Prag , Heather Smith , Libby Taylor , William T. Trotter

We consider the problem of determining the maximum number of pairs $F\subseteq F'$ in a family $\mathcal{F}\subseteq 2^{[n]}$ that avoids certain posets $P$ of height 2. We show that for any such $P$ the number of pairs is…

Combinatorics · Mathematics 2021-11-17 Dániel Nagy , Balázs Patkós

We prove that the dimension of every poset whose comparability graph has maximum degree $\Delta$ is at most $\Delta\log^{1+o(1)} \Delta$. This result improves on a 30-year old bound of F\"uredi and Kahn, and is within a $\log^{o(1)}\Delta$…

Combinatorics · Mathematics 2020-02-17 Alex Scott , David R. Wood

Given a finite poset $\mathcal{P}$, a family $\mathcal{F}$ of elements in the Boolean lattice is induced-$\mathcal{P}$-saturated if $\mathcal{F}$ contains no copy of $\mathcal{P}$ as an induced subposet but every proper superset of…

Combinatorics · Mathematics 2019-08-06 Ryan R. Martin , Heather C. Smith , Shanise Walker