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In this paper we study a variation of the accessibility percolation model, this is also motivated by evolutionary biology and evolutionary computation. Consider a tree whose vertices are labeled with random numbers. We study the probability…

Probability · Mathematics 2018-06-28 Frank Duque , Alejandro Roldán-Correa , Leon A. Valencia

We study two related probabilistic models of permutations and trees biased by their number of descents. Here, a descent in a permutation $\sigma$ is a pair of consecutive elements $\sigma(i), \sigma(i+1)$ such that $\sigma(i) >…

Probability · Mathematics 2023-12-19 Paul Thévenin , Stephan Wagner

We calculate the exact number of contours of size $n$ containing a fixed vertex in $d$-ary trees and provide sharp estimates for this number for more general trees. We also obtain a characterization of the locally finite trees with…

Combinatorics · Mathematics 2016-12-21 Noga Alon , Rodrigo Bissacot , Eric Ossami Endo

Connected Vertex Cover is one of the classical problems of computer science, already mentioned in the monograph of Garey and Johnson. Although the optimization and decision variants of finding connected vertex covers of minimum size or…

Data Structures and Algorithms · Computer Science 2016-02-25 Petr A. Golovach , Pinar Heggernes , Dieter Kratsch

A vertex cover on a graph is a set of vertices in which each edge of the graph is adjacent to at least one vertex in the set. The Minimal Vertex Cover (MVC) Problem concerns finding vertex covers with a smallest cardinality. The MVC problem…

Statistical Mechanics · Physics 2025-11-04 Yu-Tao Li , Chun-Yan Zhao , Jin-Hua Zhao

We show that the average order of a dominating set of a forest graph $G$ on $n$ vertices with no isolated vertices is at most $2n/3$. Moreover, the equality is achieved if and only if every non-leaf vertex of $G$ is a support vertex with…

Combinatorics · Mathematics 2022-08-23 Aysel Erey

Motivated by the work of Lov\'asz and Szegedy on the convergence and limits of dense graph sequences, we investigate the convergence and limits of finite trees with respect to sampling in normalized distance. Based on separable real trees,…

Combinatorics · Mathematics 2021-10-19 Gábor Elek , Gábor Tardos

Let $T$ be a random tree taken uniformly at random from the family of labelled trees on $n$ vertices. In this note, we provide bounds for $c(n)$, the number of sub-trees of $T$ that hold asymptotically almost surely. With computer support…

Combinatorics · Mathematics 2018-08-16 Bogumil Kaminski , Pawel Pralat

We solve a conjecture by Becker et al. (arXiv:2404.05963) on the topic of zero forcing regarding the number of minimal forts of a tree. They conjectured and we prove $\mathcal{F}_{T_n} \le \binom{n}{2} \mathcal{F}_{P_n}$ where…

Combinatorics · Mathematics 2026-05-11 Nguyen Hoang Dat , Franklin H. J. Kenter

The minimum vertex cover (Min-VC) problem is a well-known NP-hard problem. Earlier studies illustrate that the problem defined over the Erd\"{o}s-R\'{e}nyi random graph with a mean degree $c$ exhibits computational difficulty in searching…

Statistical Mechanics · Physics 2019-12-11 Masato Suzuki , Yoshiyuki Kabashima

We consider a random tree and introduce a metric in the space of trees to define the ``mean tree'' as the tree minimizing the average distance to the random tree. When the resulting metric space is compact we have laws of large numbers and…

Probability · Mathematics 2007-05-23 David Balding , Pablo A. Ferrari , Ricardo Fraiman , Mariela Sued

In this paper and a companion paper, we prove that, if $m$ is sufficiently large, every graph on $m+1$ vertices that has a universal vertex and minimum degree at least $\lfloor \frac{2m}{3} \rfloor$ contains each tree $T$ with $m$ edges as…

Combinatorics · Mathematics 2022-07-21 Bruce Reed , Maya Stein

An L-shaped embedding of a tree in a point set is a planar drawing of the tree where the vertices are mapped to distinct points and every edge is drawn as a sequence of two axis-aligned line segments. There has been considerable work on…

Computational Geometry · Computer Science 2020-05-01 Torsten Mütze , Manfred Scheucher

In this work, we are interested in the set of visited vertices of a tree $\mathbb{T}$ by a randomly biased random walk $\mathbb{X}:=(X_n,n \in \mathbb{N})$. The aim is to study a generalized range, that is to say the volume of the trace of…

Probability · Mathematics 2024-09-20 Pierre Andreoletti , Alexis Kagan

Let $\T_{n}$ be the set of rooted labeled trees on $\set{0,...,n}$. A maximal decreasing subtree of a rooted labeled tree is defined by the maximal subtree from the root with all edges being decreasing. In this paper, we study a new…

Combinatorics · Mathematics 2022-03-22 Seunghyun Seo , Heesung Shin

A subtree of a tree is any induced subgraph that is again a tree (i.e., connected). The mean subtree order of a tree is the average number of vertices of its subtrees. This invariant was first analyzed in the 1980s by Jamison. An intriguing…

Combinatorics · Mathematics 2021-06-11 Stijn Cambie , Stephan Wagner , Hua Wang

Let $T$ be a regular rooted tree. For every natural number $n$, let $B_n$ be the finite subtree of vertices with graph distance at most $n$ from the root. Consider the following forest-fire model on $B_n$: Each vertex can be "vacant" or…

Probability · Mathematics 2014-04-02 Robert Graf

Betweenness centrality of a vertex in a graph measures the fraction of shortest paths going through the vertex. This is a basic notion for determining the importance of a vertex in a network. The k-betweenness centrality of a vertex is…

Social and Information Networks · Computer Science 2016-07-11 Benjamin Fish , Rahul Kushwaha , Gyorgy Turan

We consider so-called simple families of labelled trees, which contain, e.g., ordered, unordered, binary and cyclic labelled trees as special instances, and study the global and local behaviour of the number of inversions. In particular we…

Combinatorics · Mathematics 2011-01-26 Alois Panholzer , Georg Seitz

A spanning tree of an unweighted graph is a minimum average stretch spanning tree if it minimizes the ratio of sum of the distances in the tree between the end vertices of the graph edges and the number of graph edges. We consider the…

Data Structures and Algorithms · Computer Science 2014-04-15 N. S. Narayanaswamy , G. Ramakrishna
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