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Carmesin has extended Robertson and Seymour's tree-of-tangles theorem to the infinite tangles of locally finite infinite graphs. We extend it further to the infinite tangles of all infinite graphs. Our result has a number of applications…

Combinatorics · Mathematics 2021-01-20 Ann-Kathrin Elm , Jan Kurkofka

In this paper we study the eigenvalues of the laplacian matrices of the cyclic graphs with one edge of weight $\alpha$ and the others of weight $1$. We denote by $n$ the order of the graph and suppose that $n$ tends to infinity. We notice…

Functional Analysis · Mathematics 2025-04-28 Sergei M. Grudsky , Egor A. Maximenko , Alejandro Soto-González

We consider a non self-adjoint Laplacian on a directed graph with non symmetric edge weights. We give necessary conditions for this Laplacian to be sectorial. We introduce a special self-adjoint operator and compare its essential spectrum…

Spectral Theory · Mathematics 2018-01-08 Colette Anné , Marwa Balti , Nabila Torki-Hamza

We show that if a graph admits a packing and a covering both consisting of $\lambda$ many spanning trees, where $\lambda$ is some infinite cardinal, then the graph also admits a decomposition into $\lambda$ many spanning trees. For finite…

Combinatorics · Mathematics 2024-05-27 Joshua Erde , Pascal Gollin , Atilla Joó , Paul Knappe , Max Pitz

We prove that every oriented tree on $n$ vertices with bounded maximum degree appears as a spanning subdigraph of every directed graph on $n$ vertices with minimum semidegree at least $n/2+o(n)$. This can be seen as a directed graph…

Combinatorics · Mathematics 2026-05-20 Richard Mycroft , Tássio Naia

For a uniform random labelled tree, we find the limiting distribution of tree parameters which are stable (in some sense) with respect to local perturbations of the tree structure. The proof is based on the martingale central limit theorem…

Combinatorics · Mathematics 2022-06-16 Mikhail Isaev , Angus Southwell , Maksim Zhukovskii

Laplacian Eigenvectors of the graph constructed from a data set are used in many spectral manifold learning algorithms such as diffusion maps and spectral clustering. Given a graph constructed from a random sample of a $d$-dimensional…

Machine Learning · Statistics 2015-10-29 Xu Wang

The generalized composition graph is used by Cardoso and some researchers for factorization of the adjacency spectrum and Laplacian of a simple graph. Because the generalized composition graph is an example of a set-theoretic linear operad,…

Combinatorics · Mathematics 2026-05-01 Jean Liendo

In this paper the Erdos-Rado theorem is generalized to the class of well founded trees.

Logic · Mathematics 2020-02-25 Esther Gruenhut , Saharon Shelah

We conjecture a new lower bound on the algebraic connectivity of a graph that involves the number of vertices of high eccentricity in a graph. We prove that this lower bound implies a strengthening of the Laplacian Spread Conjecture. We…

Combinatorics · Mathematics 2022-01-13 Wayne Barrett , Emily Evans , H. Tracy Hall , Mark Kempton

We consider compact metric graphs with an arbitrary self adjoint realisation of the differential Laplacian. After discussing spectral properties of Laplacians, we prove several versions of trace formulae, relating Laplace spectra to sums…

Mathematical Physics · Physics 2015-05-13 Jens Bolte , Sebastian Endres

In a paper by Nishikawa and Motter, a quantity called the normalized spread of the Laplacian eigenvalues is used to measure the synchronizability of certain network dynamics. Through simulations, and without theoretical validation, it is…

Optimization and Control · Mathematics 2026-01-09 Susie Lu , John Urschel , Ji Liu

Let $G$ be a simple connected undirected graph. The Laplacian spectral ratio of $G$, denoted by $R_L(G)$, is defined as the quotient between the largest and second smallest Laplacian eigenvalues of $G$, which is closely related to the…

Combinatorics · Mathematics 2023-02-22 Zhen Lin , Jiajia Wang , Min Cai

We demonstrate the versatility of the tangle-tree duality theorem for abstract separation systems by using it to prove tree-of-tangles theorems. This approach allows us to strengthen some of the existing tree-of-tangles theorems by bounding…

Combinatorics · Mathematics 2025-05-20 Christian Elbracht , Jay Lilian Kneip , Maximilian Teegen

In this paper we prove a compactness theorem for a sequence of harmonic maps which are defined on a converging sequence of Riemannian manifolds.

Differential Geometry · Mathematics 2014-12-02 Zahra Sinaei

Restrictions of incidence-preserving path maps produce an oriented hypergraphic All Minors Matrix-tree Theorems for Laplacian and adjacency matrices. The images of these maps produce a locally signed graphic, incidence generalization, of…

Combinatorics · Mathematics 2020-09-29 Ellen Robinson , Lucas J. Rusnak , Martin Schmidt , Piyush Shroff

We define and prove isomorphisms between three combinatorial classes involving labeled trees. We also give an alternative proof by means of generating functions.

Combinatorics · Mathematics 2020-04-14 Ali Chouria , Vlad-Florin Drǎgoi , Jean-Gabriel Luque

The Riemann-Roch theorem is of utmost importance in the algebraic geometric theory of compact Riemann surfaces. It tells us how many linearly independent meromorphic functions there are having certain restrictions on their poles. The aim of…

Complex Variables · Mathematics 2007-06-20 A. Lesfari

We consider a set of measures on the real line and the corresponding system of multiple orthogonal polynomials (MOPs) of the first and second type. Under some very mild assumptions, which are satisfied by Angelesco systems, we define…

Classical Analysis and ODEs · Mathematics 2019-12-02 Alexander I. Aptekarev , Sergey A. Denisov , Maxim L. Yattselev

This paper explores interlacing inequalities in the Laplacian spectrum of signed cycles and investigates interlacing relationship between the spectrum of the net-Laplacian of a signed graph and its subgraph formed by removing a vertex…

Combinatorics · Mathematics 2023-10-19 Satyam Guragain , Ravi Srivastava