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Wu, Zhang and Li [4] conjectured that the set of vertices of any simple graph $G$ can be equitably partitioned into $\lceil(\Delta(G)+1)/2\rceil$ subsets so that each of them induces a forest of $G$. In this note, we prove this conjecture…

组合数学 · 数学 2012-11-22 Xin Zhang , Jian-Liang Wu

In the present paper we establish a clear correspondence between probabilities of certain edges belonging to a realization of the uniform spanning tree (UST), and the states of a fermionic Gaussian free field. Namely, we express the…

概率论 · 数学 2023-12-27 Alan Rapoport

A class of graphs is bridge-addable if given a graph $G$ in the class, any graph obtained by adding an edge between two connected components of $G$ is also in the class. We prove a conjecture of McDiarmid, Steger, and Welsh, that says that…

组合数学 · 数学 2023-06-23 Guillaume Chapuy , Guillem Perarnau

We consider the problem of finding the smallest graph that contains two input trees each with at most $n$ vertices preserving their distances. In other words, we look for an isometric-universal graph with the minimum number of vertices for…

数据结构与算法 · 计算机科学 2025-06-17 Edgar Baucher , François Dross , Cyril Gavoille

Let the class A of graphs be bridge-addable; that is, whenever a graph G in A has vertices u and v in different components then the graph G+uv is in A. For a random graph sampled uniformly from the graphs in A on vertex set {1,..,n}, there…

组合数学 · 数学 2020-06-04 Colin McDiarmid

We prove that if a unimodular random rooted graph is recurrent, the number of ends of its uniform spanning tree is almost surely equal to the number of ends of the graph. Together with previous results in the transient case, this completely…

概率论 · 数学 2023-01-11 Diederik van Engelenburg , Tom Hutchcroft

Graph connectivity is a fundamental combinatorial optimization problem that arises in many practical applications, where usually a spanning subgraph of a network is used for its operation. However, in the real world, links may fail…

数据结构与算法 · 计算机科学 2022-09-13 Dimitris Fotakis , Evangelia Gergatsouli , Charilaos Pipis , Miltiadis Stouras , Christos Tzamos

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…

组合数学 · 数学 2023-11-07 Ervin Győri , Binlong Li , Nika Salia , Casey Tompkins

Connected acyclic graphs (trees) are data objects that hierarchically organize categories. Collections of trees arise in a diverse variety of fields, including evolutionary biology, public health, machine learning, social sciences and…

统计方法学 · 统计学 2025-12-01 Maria Alejandra Valdez Cabrera , Amy D Willis , Armeen Taeb

In this work, we study the color discrepancy of spanning trees in random graphs. We show that for the Erd\H{o}s-R\'enyi random graph $G(n,p)$ with $p$ above the connectivity threshold, the following holds with high probability: in every…

组合数学 · 数学 2025-11-10 Wenchong Chen , Xiao-Chuan Liu , Xu Yang

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…

物理与社会 · 物理学 2008-08-07 Luciano da Fontoura Costa , Francisco Aparecido Rodrigues

Pairwise compatibility graphs (PCGs) with non-negative integer edge weights recently have been used to describe rare evolutionary events and scenarios with horizontal gene transfer. Here we consider the case that vertices are separated by…

组合数学 · 数学 2020-05-26 Yangjing Long , Peter F. Stadler

An $\alpha$-thin tree $T$ of a graph $G$ is a spanning tree such that every cut of $G$ has at most an $\alpha$ proportion of its edges in $T$. The Thin Tree Conjecture proposes that there exists a function $f$ such that for any $\alpha >…

计算复杂性 · 计算机科学 2026-01-01 Alice Moayyedi

There are several good reasons you might want to read about uniform spanning trees, one being that spanning trees are useful combinatorial objects. Not only are they fundamental in algebraic graph theory and combinatorial geometry, but they…

概率论 · 数学 2007-05-23 Robin Pemantle

The Gy\'arf\'as tree packing conjecture asserts that any set of trees with $2,3, ..., k$ vertices has an (edge-disjoint) packing into the complete graph on $k$ vertices. Gy\'arf\'as and Lehel proved that the conjecture holds in some special…

组合数学 · 数学 2011-10-24 Dániel Gerbner , Balázs Keszegh , Cory Palmer

We show that for any fixed dense graph G and bounded-degree tree T on the same number of vertices, a modest random perturbation of G will typically contain a copy of T . This combines the viewpoints of the well-studied problems of embedding…

组合数学 · 数学 2025-05-30 Michael Krivelevich , Matthew Kwan , Benny Sudakov

Consider the following process on a simple graph without isolated vertices: Order the edges randomly and keep an edge if and only if it contains a vertex which is not contained in some preceding edge. The resulting set of edges forms a…

We give a proof for sharp estimate for the number of spanning trees using linear algebra and generalize this bound to multigraphs. In addition, we show that this bound is tight for complete graphs. In addition, we give estimates for number…

组合数学 · 数学 2022-12-01 K. V. Chelpanov

We consider the quantity $P(G)$ associated with a graph $G$ that is defined as the probability that a randomly chosen subtree of $G$ is spanning. Motivated by conjectures due to Chin, Gordon, MacPhee and Vincent on the behaviour of this…

组合数学 · 数学 2019-10-17 Stephan Wagner

An antimagic labeling of a digraph $D$ with $n$ vertices and $m$ arcs is a bijection from the set of arcs of $D$ to $\{1,2,\cdots,m\}$ such that all $n$ oriented vertex-sums are pairwise distinct, where the oriented vertex-sum of a vertex…

组合数学 · 数学 2021-11-09 Songling Shan , Xiaowei Yu