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We study edge-decompositions of highly connected graphs into copies of a given tree. In particular we attack the following conjecture by Bar\'at and Thomassen: for each tree $T$, there exists a natural number $k_T$ such that if $G$ is a…

Combinatorics · Mathematics 2012-03-09 János Barát , Dániel Gerbner

We prove that every graph which admits a tree-decomposition into finite parts has a rooted tree-decomposition into finite parts that is linked, tight and componental. As an application, we obtain that every graph without half-grid minor has…

Combinatorics · Mathematics 2024-05-14 Sandra Albrechtsen , Raphael W. Jacobs , Paul Knappe , Max Pitz

Let $T$ be a distinguished subset of vertices in a graph $G$. A $T$-\emph{Steiner tree} is a subgraph of $G$ that is a tree and that spans $T$. Kriesell conjectured that $G$ contains $k$ pairwise edge-disjoint $T$-Steiner trees provided…

Combinatorics · Mathematics 2015-08-11 Matt DeVos , Jessica McDonald , Irene Pivotto

An edge subset $S$ of a connected graph $G$ is called an anti-Kekul\'{e} set if $G-S$ is connected and has no perfect matching. We can see that a connected graph $G$ has no anti-Kekul\'{e} set if and only if each spanning tree of $G$ has a…

Combinatorics · Mathematics 2016-02-02 Baoyindureng Wu , Heping Zhang

We derive a sufficient condition for a sparse graph G on n vertices to contain a copy of a tree T of maximum degree at most d on (1-\epsilon)n vertices, in terms of the expansion properties of G. As a result we show that for fixed d\geq 2…

Combinatorics · Mathematics 2007-06-29 Noga Alon , Michael Krivelevich , Benny Sudakov

The primary objective of this paper is to investigate the notions of geometric and sequential convexity within a graph-theoretic framework, with the aim of examining various structural properties and exploring the connection between these…

General Mathematics · Mathematics 2026-04-24 Angshuman R. Goswami

We show how, given a sufficiently large point cloud sampled from an embedded 2-manifold in $\mathbb{R}^n$, we may obtain a global representation as a cell complex with vertices given by a representative subset of the point cloud. The vertex…

Numerical Analysis · Mathematics 2018-09-05 Tyrus Berry , Steven Schluchter

We introduce a method for creating a special type of tree, called a tree position, from a weighted graph. Leaves of the tree correspond to vertices of the original graph, and the tree edges contain information which can be used to partition…

Combinatorics · Mathematics 2014-08-19 R. Sean Bowman , Douglas R. Heisterkamp , Jesse Johnson

We study the bounded regions in a generic slice of the hyperplane arrangement in $\mathbb{R}^n$ consisting of the hyperplanes defined by $x_i$ and $x_i+x_j$. The bounded regions are in bijection with several classes of combinatorial…

Combinatorics · Mathematics 2014-01-29 Qingchun Ren

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

For a connected labelled graph $G$, a {\em spanning tree} $T$ is a connected and an acyclic subgraph that spans all vertices of $G$. In this paper, we consider a classical combinatorial problem which is to list all spanning trees of $G$. A…

Discrete Mathematics · Computer Science 2016-07-21 K. Krishna Mohan Reddy , P. Renjith , N. Sadagopan

We prove Ehrenborg's conjecture that every connected bipartite graph $G$ with parts of size $m$ and $n$ has at most $\frac{1}{mn}\prod_{v\in V(G)} \operatorname{deg}(v)$ spanning trees, and that equality holds if and only if $G$ is a…

Combinatorics · Mathematics 2026-03-19 Boon Suan Ho

In phylogenetics, evolution is traditionally represented in a tree-like manner. However, phylogenetic networks can be more appropriate for representing evolutionary events such as hybridization, horizontal gene transfer, and others. In…

Data Structures and Algorithms · Computer Science 2024-10-18 Manuel Lafond , Vincent Moulton

This work addresses the intrinsic relationship between trees and networks (i.e. graphs). A complete (invertible) mapping is presented which allows trees to be mapped into weighted graphs and then backmapped into the original tree without…

Physics and Society · Physics 2008-08-07 Luciano da Fontoura Costa , Francisco Aparecido Rodrigues

We prove that every weighted graph contains a spanning tree subgraph of average stretch O((log n log log n)^2). Moreover, we show how to construct such a tree in time O(m log^2 n).

Data Structures and Algorithms · Computer Science 2007-05-23 Michael Elkin , Yuval Emek , Daniel A. Spielman , Shang-Hua Teng

A classical result of Koml\'os, S\'ark\"ozy and Szemer\'edi states that every $n$-vertex graph with minimum degree at least $(1/2+ o(1))n$ contains every $n$-vertex tree with maximum degree $O(n/\log{n})$ as a subgraph, and the bounds on…

Combinatorics · Mathematics 2018-03-14 Felix Joos , Jaehoon Kim

In this paper, we address the Ehrenborg's conjecture which proposes that for any bipartite graph the number of spanning trees does not exceed the product of the degrees of the vertices divided by the product of the sizes of the graph…

Combinatorics · Mathematics 2020-09-16 Albina Volkova

Chung and Graham considered the problem of minimizing the number of edges in an $n$-vertex graph containing all $n$-vertex trees as a subgraph. They showed that such a graph has at least $\frac{1}{2}n \log{n}$ edges. In this note, we…

Combinatorics · Mathematics 2023-11-07 Ervin Győri , Binlong Li , Nika Salia , Casey Tompkins

We show that for every graph $G$ that contains two edge-disjoint spanning trees, we can choose two edge-disjoint spanning trees $T_1,T_2$ of $G$ such that $|d_{T_1}(v)-d_{T_2}(v)|\leq 5$ for all $v \in V(G)$. We also prove the more general…

Combinatorics · Mathematics 2022-08-09 Florian Hörsch

We give a criterion when a planar tree-like curve, i.e. a generic immersed plane curve each double point of which cuts it into two disjoint parts, can be send by a diffeomorphism of the plane onto a curve with no inflection points. We also…

dg-ga · Mathematics 2008-02-03 Boris Shapiro