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Measures of tree balance play an important role in different research areas such as mathematical phylogenetics or theoretical computer science. The balance of a tree is usually quantified in a single number, called a balance or imbalance…

Combinatorics · Mathematics 2024-06-28 Bryan Currie , Kristina Wicke

We prove that the extension complexity of the independence polytope of every regular matroid on $n$ elements is $O(n^6)$. Past results of Wong and Martin on extended formulations of the spanning tree polytope of a graph imply a $O(n^2)$…

Combinatorics · Mathematics 2019-12-23 Manuel Aprile , Samuel Fiorini

We determine the sharp threshold for the containment of all $n$-vertex trees of bounded degree in random geometric graphs with $n$ vertices. This provides a geometric counterpart of Montgomery's threshold result for binomial random graphs,…

Combinatorics · Mathematics 2025-05-23 Michael Anastos , Sahar Diskin , Dawid Ignasiak , Lyuben Lichev , Yetong Sha

In this paper we study properties and invariants of matrix codes endowed with the rank metric, and relate them to the covering radius. We introduce new tools for the analysis of rank-metric codes, such as puncturing and shortening…

Combinatorics · Mathematics 2016-09-01 Eimear Byrne , Alberto Ravagnani

Given a rooted tree and a ranking of its leaves, what is the minimum number of inversions of the leaves that can be attained by ordering the tree? This variation of the problem of counting inversions in arrays originated in mathematical…

Data Structures and Algorithms · Computer Science 2024-07-02 Ivan Hu , Dieter van Melkebeek , Andrew Morgan

The matching energy is defined as the sum of the absolute values of the zeros of the matching polynomial of a graph, which is proposed first by Gutman and Wagner [The matching energy of a graph, Discrete Appl. Math. 160 (2012) 2177--2187].…

Combinatorics · Mathematics 2014-12-01 Tingzeng Wu , Weigen Yan , Heping Zhang

Low-rank matrix completion addresses the problem of completing a matrix from a certain set of generic specified entries. Over the complex numbers a matrix with a given entry pattern can be uniquely completed to a specific rank, called the…

Algebraic Geometry · Mathematics 2025-03-13 Mareike Dressler , Robert Krone

In this paper, we use Betti splittings of binomial edge ideals to establish improved upper and lower bounds for their regularity in the case of trees. As a consequence, we determine the exact regularity for certain classes of trees.

Commutative Algebra · Mathematics 2025-05-01 Rajiv Kumar , Paramhans Kushwaha

We prove a lower bound on the number of spanning two-forests in a graph, in terms of the number of vertices, edges, and spanning trees. This implies an upper bound on the average cut size of a random two-forest. The main tool is an identity…

Combinatorics · Mathematics 2023-08-09 Harry Richman , Farbod Shokrieh , Chenxi Wu

In this article, we are going to introduce the weighted numerical range which is a further generalization both the c-numerical range and the rank k numerical range. If the boundaries of weighted numerical ranges of two matrices (possibly of…

Functional Analysis · Mathematics 2015-06-16 Wai-Shun Cheung

We consider packing tree degree sequences in this paper. We set up a conjecture that any arbitrary number of tree degree sequences without common leaves have edge disjoint tree realizations. This conjecture is known to be true for $2$ and…

Combinatorics · Mathematics 2017-04-12 Aravind Gollakota , William Hardt , Istvan Miklos

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

In this work a composition-decomposition technique is presented that correlates tree eigenvectors with certain eigenvectors of an associated so-called skeleton forest. In particular, the matching properties of a skeleton determine the…

Combinatorics · Mathematics 2018-08-21 Torsten Sander , Jürgen W. Sander

The \textit{eccentricity matrix} $\mathcal{E}(G)$ of a connected graph $G$ is obtained from the distance matrix of $G$ by keeping the largest non-zero entries in each row and each column, and leaving zeros in the remaining ones. The…

Combinatorics · Mathematics 2022-04-01 Iswar Mahato , M. Rajesh Kannan

We study the local limit of the fixed-point forest, a tree structure associated to a simple sorting algorithm on permutations. This local limit can be viewed as an infinite random tree that can be constructed from a Poisson point process…

Probability · Mathematics 2023-06-22 Samuel Regan , Erik Slivken

We determine the maximum distance between any two of the center, centroid, and subtree core among trees with a given order. Corresponding results are obtained for trees with given maximum degree and also for trees with given diameter. The…

Combinatorics · Mathematics 2017-01-20 Heather Smith , László Székely , Hua Wang , Shuai Yuan

In this work, we present an $\Omega\left(\min\{\log \Delta, \sqrt{\log n}\}\right)$ lower bound for Maximal Matching (MM) in $\Delta$-ary trees against randomized algorithms. By a folklore reduction, the same lower bound applies to Maximal…

Distributed, Parallel, and Cluster Computing · Computer Science 2025-05-22 Seri Khoury , Aaron Schild

In this paper, we provide a polynomial time algorithm to calculate the probability of a {\it ranked} gene tree topology for a given species tree, where a ranked tree topology is a tree topology with the internal vertices being ordered. The…

Populations and Evolution · Quantitative Biology 2012-03-02 Tanja Stadler , James H. Degnan

A uniform recursive tree on $n$ vertices is a random tree where each possible $(n-1)!$ labeled recursive rooted tree is selected with equal probability. In this paper we introduce and study weighted trees, a non-uniform recursive tree model…

Probability · Mathematics 2017-12-12 Ella Hiesmayr , Ümit Işlak

In this paper, we find an upper bound for the CP-rank of a matrix over a tropical semiring, according to the vertex clique cover of the graph prescribed by the pattern of the matrix. We study the graphs that beget the patterns of matrices…

Rings and Algebras · Mathematics 2018-03-16 David Dolžan , Polona Oblak
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