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Tree shape statistics, particularly measures of tree (im)balance, play an important role in the analysis of the shape of phylogenetic trees. With applications ranging from testing evolutionary models to studying the impact of fertility…

Populations and Evolution · Quantitative Biology 2024-10-15 Sophie J. Kersting , Kristina Wicke , Mareike Fischer

An important problem in geometric computing is defining and computing similarity between two geometric shapes, e.g. point sets, curves and surfaces, etc. Important geometric and topological information of many shapes can be captured by…

Computational Geometry · Computer Science 2015-08-17 Hangjun Xu

We consider the in-plane motion of elastic strings on tree-like network, observed from the 'leaves'. We investigate the inverse problem of recovering not only the physical properties i.e. the 'optical lengths' of each string, but also the…

Analysis of PDEs · Mathematics 2025-05-29 S. A. Avdonin , G. Leugering , V. S. Mikhaylov

Spanning trees of complete bipartite graphs exhibit a rich interaction between degree sequences and graph structure. In this paper, we obtain lower bounds on the number of isomorphism classes of spanning trees in $K_{a,b}, 2 \leq a \leq b$…

Combinatorics · Mathematics 2026-03-03 Peter Johnson , Shayne Nochumson

We obtain the maximum sum-connectivity indices of graphs in the set of trees and in the set of unicyclic graphs respectively with given number of vertices and maximum degree, and determine the corresponding extremal graphs. Additionally, we…

Combinatorics · Mathematics 2012-10-19 Zhibin Du , Bo Zhou , Nenad Trinajstic

The enumeration of chemical graphs is an important topic in cheminformatics and bioinformatics, particularly in the discovery of novel drugs. These graphs are typically either tree-like multigraphs or composed of tree-like multigraphs…

Discrete Mathematics · Computer Science 2025-02-11 Muhammad Ilyas , Seemab Hayat , Naveed Ahmed Azam

A matching complex of a simple graph $G$ is a simplicial complex with faces given by the matchings of $G$. The topology of matching complexes is mysterious; there are few graphs for which the homotopy type is known. Marietti and Testa…

Combinatorics · Mathematics 2021-02-01 Marija Jelić Milutinović , Helen Jenne , Alex McDonough , Julianne Vega

We consider the eccentric graph of a graph $G$, denoted by $ecc(G)$, which has the same vertex set as $G$, and two vertices in the eccentric graph are adjacent iff their distance in $G$ is equal to the eccentricity of one of them. In this…

Combinatorics · Mathematics 2024-07-30 Sezer Sorgun , Esma Elyemani

It is known that there is an alternative characterization of characteristic vertices for trees with positive weights on their edges via Perron values and Perron branches. Moreover, the algebraic connectivity of a tree with positive edge…

Combinatorics · Mathematics 2022-03-18 Swetha Ganesh , Sumit Mohanty

Topological photonics provides a powerful framework to describe and understand many nontrivial wave phenomena in complex electromagnetic platforms. The topological index of a physical system is an abstract global property that depends on…

Mesoscale and Nanoscale Physics · Physics 2023-07-05 Mario G. Silveirinha

A hierarchical structure describing the inter-relationships of species has long been a fundamental concept in systematic biology, from Linnean classification through to the more recent quest for a 'Tree of Life.' In this paper we use an…

Populations and Evolution · Quantitative Biology 2009-08-21 Andreas Dress , Vincent Moulton , Mike Steel , Taoyang Wu

A spanning tree of a graph is a connected subgraph on all vertices with the minimum number of edges. The number of spanning trees in a graph $G$ is given by Matrix Tree Theorem in terms of principal minors of Laplacian matrix of $G$. We…

Combinatorics · Mathematics 2018-05-15 Keivan Hassani Monfared , Sudipta Mallik

We study that over some types of trees with a given number of vertices, which trees minimize or maximize the total number of subtrees. Trees minimizing (resp. maximizing) the total number of subtrees usually maximize (resp. minimize) the…

Combinatorics · Mathematics 2012-04-30 Shuchao Li , Shujing Wang

An evolutionary tree is a rooted tree where each internal vertex has at least two children and where the leaves are labeled with distinct symbols representing species. Evolutionary trees are useful for modeling the evolutionary history of…

Computational Engineering, Finance, and Science · Computer Science 2007-05-23 Ming-Yang Kao

Topology is a central concept of mathematics, which allows us to distinguish two isolated rings with linked ones. In material science, researchers discovered topologically different carbon allotropes in a form of a cage, a tube, and a…

Mesoscale and Nanoscale Physics · Physics 2023-04-05 Shinichi Saito , Isao Tomita

Among many topological indices of trees the sum of distances $\sigma(T)$ and the number of subtrees $F(T)$ have been a long standing pair of graph invariants that are well known for their negative correlation. That is, among various given…

Combinatorics · Mathematics 2017-12-05 Shuchao Li , Hua Wang , Shujing Wang

Motivated by the recently introduced topological index, the Somber index, we define a new topological index of a graph in this paper, we call it Sombor coindex. The Sombor coindex is defined by considering analogous contributions from the…

Combinatorics · Mathematics 2022-09-21 Phanjoubam Chinglensana , Sainkupar Mn Mawiong

Networks are important representations in computer science to communicate structural aspects of a given system of interacting components. The evolution of a network has several topological properties that can provide us information on the…

Social and Information Networks · Computer Science 2020-04-30 Joao Pita Costa , Tihana Galinac Grbac

Let $R$ be a not necessarily commutative ring with $1.$ In the present paper we first introduce a notion of quasi-orderings, which axiomatically subsumes all the orderings and valuations on $R$. We proceed by uniformly defining a coarsening…

Rings and Algebras · Mathematics 2020-04-14 Simon Müller

The paper attempts to validate the effectiveness of tree classifiers to classify tabla strokes especially the ones which are overlapping in nature. It uses decision tree, ID3 and random forest as classifiers. A custom made data sets of 650…

Sound · Computer Science 2018-01-08 Subodh Deolekar , Siby Abraham