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Applications in chemistry motivated mathematicians to define different topological indices for different types of graphs. The Hyper-Zagreb index (HM) is an important tool as it integrates the first and the second Zagreb indices. In this…

Combinatorics · Mathematics 2018-09-12 Hassan Rezapour , Ramin Nasiri , Seyedahmad Mousavi

We establish maximal trees and graphs for the difference of average distance and proximity proving thus the corresponding conjecture posed in [4]. We also establish maximal trees for the difference of average eccentricity and remoteness and…

Combinatorics · Mathematics 2020-10-22 Jelena Sedlar

A cactus is a connected graph in which any two cycles have at most one common vertex. We determine the unique graph that maximizes the distance spectral radius over all cacti with fixed numbers of vertices and cycles, and thus prove a…

Combinatorics · Mathematics 2023-03-20 Yanna Wang , Bo Zhou

Topological indices are graph-theoretic descriptors that play a crucial role in mathematical chemistry, capturing the structural characteristics of molecules and enabling the prediction of their physicochemical properties. A widely studied…

Discrete Mathematics · Computer Science 2025-11-26 Sébastien Bonte , Gauvain Devillez , Valentin Dusollier , Alain Hertz , Hadrien Mélot , David Schindl

Phylogenetic trees are a central tool in understanding evolution. They are typically inferred from sequence data, and capture evolutionary relationships through time. It is essential to be able to compare trees from different data sources…

Populations and Evolution · Quantitative Biology 2017-10-31 Michelle Kendall , Caroline Colijn

Chemical graphs are simple undirected connected graphs, where vertices represent atoms in a molecule and edges represent chemical bonds. A degree-based topological index is a molecular descriptor used to study specific physicochemical…

The atom-bond-connectivity (ABC) index is one of the well-investigated degree-based topological indices. The atom-bond sum-connectivity (ABS) index is a modified version of the ABC index, which was introduced recently. The primary goal of…

The zeroth-order general Randi\'{c} index $R^{0}_{a}$ of a digraph $D$ is the sum of $(d^{+}_{v})^{a}+(d^{-}_{w})^{a}$ over all arcs $vw$ of $D$, where $a$, $d^{+}_{v}$ and $d^{-}_{w}$ are an arbitrary real number, the out-degree of the…

Combinatorics · Mathematics 2022-06-06 Jiaxiang Yang , Hanyuan Deng

Signs of hierarchy are prevalent in a wide range of systems in nature and society. One of the key problems is quantifying the importance of hierarchical organisation in the structure of the network representing the interactions or…

Physics and Society · Physics 2016-01-25 Dániel Czégel , Gergely Palla

Maximum parsimony distance is a measure used to quantify the dissimilarity of two unrooted phylogenetic trees. It is NP-hard to compute, and very few positive algorithmic results are known due to its complex combinatorial structure. Here we…

Data Structures and Algorithms · Computer Science 2020-04-07 Mark Jones , Steven Kelk , Leen Stougie

Oblique decision trees have attracted attention due to their potential for improved classification performance over traditional axis-aligned decision trees. However, methods that rely on exhaustive search to find oblique splits face…

Machine Learning · Computer Science 2025-05-09 Andrew D. Laack

We introduce a cluster evaluation technique called Tree Index. Our Tree Index algorithm aims at describing the structural information of the clustering rather than the quantitative format of cluster-quality indexes (where the representation…

Machine Learning · Computer Science 2020-03-25 A. H. Beg , Md Zahidul Islam , Vladimir Estivill-Castro

The leap eccentric connectivity index of $G$ is defined as $$L\xi^{C}(G)=\sum_{v\in V(G)}d_{2}(v|G)e(v|G)$$ where $d_{2}(v|G) $ be the second degree of the vertex $v$ and $e(v|G)$ be the eccentricity of the vertex $v$ in $G$. In this paper,…

Combinatorics · Mathematics 2021-04-09 Ling Song , Zikai Tang

We obtained Pearson's coefficient of strongly correlated recursive networks growing by preferential attachment of every new vertex by $m$ edges. We found that the Pearson coefficient is exactly zero in the infinite network limit for the…

Statistical Mechanics · Physics 2015-05-14 S. N. Dorogovtsev , A. L. Ferreira , A. V. Goltsev , J. F. F. Mendes

Inference of species networks from genomic data under the Network Multispecies Coalescent Model is currently severely limited by heavy computational demands. It also remains unclear how complicated networks can be for consistent inference…

Populations and Evolution · Quantitative Biology 2022-05-10 Elizabeth S. Allman , Hector Baños , Jonathan D. Mitchell , John A. Rhodes

We demonstrate how sophisticated graph properties, such as small distances and scale-free degree distributions, arise naturally from a reinforcement mechanism on layered graphs. Every node is assigned an a-priori i.i.d. fitness with…

Probability · Mathematics 2020-06-02 Markus Heydenreich , Christian Hirsch

The discrete membrane model is a Gaussian random interface whose inverse covariance is given by the discrete biharmonic operator on a graph. In literature almost all works have considered the field as indexed over $\mathbb{Z}^d$, and this…

Probability · Mathematics 2022-10-20 Alessandra Cipriani , Biltu Dan , Rajat Subhra Hazra , Rounak Ray

Large language models achieve strong reasoning performance, yet existing decoding strategies either explore blindly (random sampling) or redundantly (independent multi-sampling). We propose Entropy-Tree, a tree-based decoding method that…

Computation and Language · Computer Science 2026-01-23 Longxuan Wei , Yubo Zhang , Zijiao Zhang , Zhihu Wang , Shiwan Zhao , Tianyu Huang , Huiting Zhao , Chenfei Liu , Shenao Zhang , Junchi Yan

The intraclass correlation coefficient (ICC) is a classical index of measurement reliability. With the advent of new and complex types of data for which the ICC is not defined, there is a need for new ways to assess reliability. To meet…

Methodology · Statistics 2020-04-29 Meng Xu , Philip T. Reiss , Ivor Cribben

An independent edge set of graph $G$ is a matching, and is maximal if it is not a proper subset of any other matching of $G$. The number of all the maximal matchings of $G$ is denoted by $\Psi(G)$. In this paper, an algorithm to count…

Combinatorics · Mathematics 2025-06-11 Lingjuan Shi , Wei Li , Kai Deng