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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

A variant of the Erd\H{o}s-S\'os conjecture, posed by Havet, Reed, Stein and Wood, states that every graph with minimum degree at least $\lfloor 2k/3 \rfloor$ and maximum degree at least $k$ contains a copy of every tree with $k$ edges.…

Combinatorics · Mathematics 2025-12-19 Alexey Pokrovskiy , Leo Versteegen , Ella Williams

The Hosoya index $Z (G)$ of a graph $G$ is defined as the total number of edge independent sets of $G$. In this paper, we extend the research of [J. Ou, On extremal unicyclic molecular graphs with maximal Hosoya index, \textit{Discrete…

Combinatorics · Mathematics 2011-05-30 Guihai Yu , Lihua Feng , Aleksandar Ilic

A complex unit gain graph ($ \mathbb{T} $-gain graph), $ \Phi=(G, \varphi) $ is a graph where the gain function $ \varphi $ assigns a unit complex number to each orientation of an edge of $ G $ and its inverse is assigned to the opposite…

Combinatorics · Mathematics 2023-12-29 Aniruddha Samanta , M. Rajesh Kannan

We discuss a notion of convergence for binary trees that is based on subtree sizes. In analogy to recent developments in the theory of graphs, posets and permutations we investigate some general aspects of the topology, such as a…

Combinatorics · Mathematics 2024-02-14 Rudolf Grübel

A dissociation set of a graph is a set of vertices which induces a subgraph with maximum degree less than or equal to one. The dissociation number of a graph is the maximum cardinality of its dissociation sets. In this paper, we study the…

Combinatorics · Mathematics 2023-09-28 Zejun Huang , Jiahui Liu , Xinwei Zhang

A fermion ground state energy functional is set up in terms of particle density, relative pair density, and kinetic energy tensor density. It satisfies a minimum principle if constrained by a complete set of compatibility conditions. A…

Chemical Physics · Physics 2009-10-17 Bin Liu , Jerome K. Percus

The construction of cut trees (also known as Gomory-Hu trees) for a given graph enables the minimum-cut size of the original graph to be obtained for any pair of vertices. Cut trees are a powerful back-end for graph management and mining,…

Data Structures and Algorithms · Computer Science 2016-09-29 Takuya Akiba , Yoichi Iwata , Yosuke Sameshima , Naoto Mizuno , Yosuke Yano

This note derives asymptotic upper and lower bounds for the number of planted plane trees on $n$ nodes assigned labels from the set $\{1,2,\ldots, k\}$ with the restriction that on any path from the root to a leaf, the labels must strictly…

Combinatorics · Mathematics 2026-03-04 Tsun-Ming Cheung , Luc Devroye , Marcel K. Goh

Fong et al. (The game chromatic index of some trees with maximum degree four and adjacent degree-four vertices, J. Comb Optim 36 (2018) 1-12) proved that the game chromatic index of any tree $T$ of maximum degree 4 whose degree-four…

Combinatorics · Mathematics 2019-04-03 Wai Lam Fong , Wai Hong Chan

Defining the energy function as the negative logarithm of the density, we explore the energy landscape of a distribution via the tree of sublevel sets of its energy. This tree represents the hierarchy among the connected components of the…

Applications · Statistics 2009-01-27 Qing Zhou , Wing Hung Wong

Optimizing chemical properties is a challenging task due to the vastness and complexity of chemical space. Here, we present a generative energy-based architecture for implicit chemical property optimization, designed to efficiently generate…

Biomolecules · Quantitative Biology 2025-06-19 Luca Miglior , Lorenzo Simone , Marco Podda , Davide Bacciu

In this paper, we introduce two families of planar and self-similar graphs which have small-world properties. The constructed models are based on an iterative process where each step of a certain formulation of modules results in a final…

Combinatorics · Mathematics 2024-04-19 Muhammed Alaa Morsy , Mohamed Anwar , Abdallah Aboutahoun

A tree with $n$ vertices has at most $95^{n/13}$ minimal dominating sets. The growth constant $\lambda = \sqrt[13]{95} \approx 1.4194908$ is best possible. It is obtained in a semi-automatic way as a kind of "dominant eigenvalue" of a…

Discrete Mathematics · Computer Science 2019-03-13 Günter Rote

We prove, that every connected graph with $s$ vertices of degree 3 and $t$ vertices of degree at least~4 has a spanning tree with at least ${2\over 5}t +{1\over 5}s+\alpha$ leaves, where $\alpha \ge {8\over 5}$. Moreover, $\alpha \ge 2$ for…

Combinatorics · Mathematics 2014-05-29 D. V. Karpov

The decomposition of a density function on a domain into a minimal sum of unimodal components is a fundamental problem in statistics, leading to the topological invariant of unimodal category of a density. This paper gives an efficient…

Algebraic Topology · Mathematics 2018-06-27 Yuliy Baryshnikov , Robert Ghrist

Trees are partial orderings where every element has a linearly ordered set of smaller elements. We define and study several natural notions of completeness of trees, extending Dedekind completeness of linear orders and Dedekind-MacNeille…

Combinatorics · Mathematics 2023-01-18 Valentin Goranko , Ruaan Kellerman , Alberto Zanardo

Energy systems optimization problems are complex due to strongly non-linear system behavior and multiple competing objectives, e.g. economic gain vs. environmental impact. Moreover, a large number of input variables and different variable…

As an alternative to parsimony analyses, stochastic models have been proposed (Lewis, 2001), (Nylander, et al., 2004) for morphological characters, so that maximum likelihood or Bayesian analyses may be used for phylogenetic inference. A…

Populations and Evolution · Quantitative Biology 2009-12-20 Elizabeth S. Allman , Mark T. Holder , John A. Rhodes

Maxmin trees are trees that consist of nodes that are either local minimums or maximums. Such trees were first studied by Postnikov. Later Dugan, Glennon, Gunnells, and Steingrimsson introduced the concept of weight to these trees and…

Combinatorics · Mathematics 2023-10-25 Emmy Huang , Ray Tang