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Let $T(G)$ be the size of the largest induced tree of $G$, and let $G_{n,p}$ be the binomial random graph. Kamaldinov, Skorkin, and Zhukovskii proved that $T(G_{n,p})$ equals one of two consecutive values with high probability if $p$ is…

Combinatorics · Mathematics 2026-03-10 Jakob Hofstad

Let $(R, \sim )$ be the Rado graph, $Emb (R)$ the monoid of its self-embeddings, $\Pi (R)=\{ f[R]: f\in Emb (R)\}$ the set of copies of $R$ contained in $R$, and ${\mathcal I}_R$ the ideal of subsets of $R$ which do not contain a copy of…

Logic · Mathematics 2017-09-26 Miloš S. Kurilić , Stevo Todorčević

Geometric embedding of graphs in a point set in the plane is a well known problem. In this paper, the complexity of a variant of this problem, where the point set is bounded by a simple polygon, is considered. Given a point set in the plane…

Computational Geometry · Computer Science 2009-08-28 Alireza Bagheri , Mohammadreza Razzazi

We study three different poset structures on the set of all compositions. In the first case, the covering relation consists of inserting a part of size one to the left or to the right, or increasing the size of some part by one. The…

Combinatorics · Mathematics 2007-05-23 Jan Snellman

We continue the study of $(\mathrm{tw},\omega)$-bounded graph classes, that is, hereditary graph classes in which the treewidth can only be large due to the presence of a large clique, with the goal of understanding the extent to which this…

Combinatorics · Mathematics 2023-12-19 Clément Dallard , Martin Milanič , Kenny Štorgel

For posets $P$ and $Q$, extremal and saturation problems about weak and strong $P$-free subposets of $Q$ have been studied mostly in the case $Q$ is the Boolean poset $Q_n$, the poset of all subsets of an $n$-element set ordered by…

Combinatorics · Mathematics 2021-11-10 Dániel Gerbner , Dániel T. Nagy , Balázs Patkós , Máté Vizer

For a graph G, let t(G) denote the maximum number of vertices in an induced subgraph of G that is a tree. In this paper, we study the problem of bounding t(G) for graphs which do not contain a complete graph K_r on r vertices. This problem…

Combinatorics · Mathematics 2008-10-25 Jacob Fox , Po-Shen Loh , Benny Sudakov

The tree-independence number of a graph is the minimum, over all tree-decompositions of the graph, of the maximum size of an independent set contained in a bag. Graph classes of bounded tree-independence number have strong structural and…

An $N$-free poset is a poset whose comparability graph does not embed an induced path with four vertices. We use the well-quasi-order property of the class of countable $N$-free posets and some labelled ordered trees to show that a…

Combinatorics · Mathematics 2023-01-09 Davoud Abdi

Rebalancing schemes for dynamic binary search trees are numerous in the literature, where the goal is to maintain trees of low height, either in the worst-case or expected sense. In this paper we study randomized rebalancing schemes for…

Data Structures and Algorithms · Computer Science 2024-04-15 Gerth Stølting Brodal

We consider the poset of weighted partitions $\Pi_n^w$, introduced by Dotsenko and Khoroshkin in their study of a certain pair of dual operads. The maximal intervals of $\Pi_n^w$ provide a generalization of the lattice $\Pi_n$ of…

Combinatorics · Mathematics 2017-11-21 Rafael S. González D'León , Michelle L. Wachs

For a fixed poset $\mathcal P$ we say that a family $\mathcal F\subseteq\mathcal P([n])$ is $\mathcal P$-saturated if it does not contain an induced copy of $\mathcal P$, but whenever we add a new set to $\mathcal F$, we form an induced…

Combinatorics · Mathematics 2026-03-10 Maria-Romina Ivan , Sean Jaffe

A proper vertex of a rooted tree with totally ordered vertices is a vertex that is less than all its proper descendants. We count several kinds of labeled rooted trees and forests by the number of proper vertices. Our results are all…

Combinatorics · Mathematics 2013-04-02 Ira M. Gessel , Seunghyun Seo

We address several related problems on combinatorial discrepancy of trees in a setting introduced by Erd\H{o}s, F\"{u}redi, Loebl and S\'{o}s. Given a fixed tree $T$ on $n$ vertices and an edge-colouring of the complete graph $K_n$, for…

Combinatorics · Mathematics 2024-10-23 Lawrence Hollom , Lyuben Lichev , Adva Mond , Julien Portier

In this thesis, we present quantitative Ramsey-type results in the setting of finite sets that are equipped with a partial order, so-called posets. A prominent example of a poset is the Boolean lattice $Q_n$, which consists of all subsets…

Combinatorics · Mathematics 2024-09-16 Christian Winter

A poset is (3+1)-free if it does not contain the disjoint union of chains of length 3 and 1 as an induced subposet. These posets are the subject of the (3+1)-free conjecture of Stanley and Stembridge. Recently, Lewis and Zhang have…

Combinatorics · Mathematics 2014-04-18 Mathieu Guay-Paquet , Alejandro H. Morales , Eric Rowland

The independence number of a tree decomposition is the size of a largest independent set contained in a single bag. The tree-independence number of a graph $G$ is the minimum independence number of a tree decomposition of $G$. As shown…

Data Structures and Algorithms · Computer Science 2026-01-23 Daniel Lokshtanov , Michał Pilipczuk , Paweł Rzążewski

The input to the agreement problem is a collection $P = \{T_1, T_2, \dots , T_k\}$ of phylogenetic trees, called input trees, over partially overlapping sets of taxa. The question is whether there exists a tree $T$, called an agreement…

Data Structures and Algorithms · Computer Science 2020-02-25 David Fernández-Baca , Lei Liu

Classical problems of sorting and searching assume an underlying linear ordering of the objects being compared. In this paper, we study a more general setting, in which some pairs of objects are incomparable. This generalization is relevant…

Data Structures and Algorithms · Computer Science 2007-07-12 Constantinos Daskalakis , Richard M. Karp , Elchanan Mossel , Samantha Riesenfeld , Elad Verbin

In this paper we consider the classical problem of computing linear extensions of a given poset which is well known to be a difficult problem. However, in our setting the elements of the poset are multivariate polynomials, and only a small…

Combinatorics · Mathematics 2021-03-05 Shane Kepley , Konstantin Mischaikow , Lun Zhang
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