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We present an exact formula for the ordinary generating series of the simple paths between any two vertices of a graph. Our formula involves the adjacency matrix of the connected induced subgraphs and remains valid on weighted and directed…

Combinatorics · Mathematics 2018-10-30 Pierre-Louis Giscard , Paul Rochet

In this paper, we investigate some relations between the invariants (including vertex and edge connectivity and forwarding indices) of a graph and its Laplacian eigenvalues. In addition, we present a sufficient condition for the existence…

Combinatorics · Mathematics 2014-07-23 Rong-Ying Pan , Jing Yan , Xiao-Dong Zhang

Matchings were among the earliest motivations for graph theory. They subsequently remained a central goal, inspiring the development of new tools that went well beyond problems directly concerning matchings. These tools proved widely…

Combinatorics · Mathematics 2026-02-05 András Sebő

In the era o fdat commodification,the pricing o fgraph data presents unique challenges that differ significantly from traditional data markets. This paper addresses the critical issue of node pricing within graph structures, an area that…

Databases · Computer Science 2025-04-15 Huiju Wang , Yuanyuan Gao , Zhengkui Wang , Xiao Yue

Let $\phi \colon \Gamma_2 \rightarrow \Gamma_1$ be a harmonic morphism of connected graphs. We show that an arithmetical structure on $\Gamma_1$ can be pulled back via $\phi$ to an arithmetical structure on $\Gamma_2$. We then show that…

Combinatorics · Mathematics 2025-04-14 Kassie Archer , Caroline Melles

A well-known conjecture of Richard Stanley posits that the $h$-vector of the independence complex of a matroid is a pure ${\mathcal O}$-sequence. The conjecture has been established for various classes but is open for graphic matroids. A…

Combinatorics · Mathematics 2023-08-11 Preston Cranford , Anton Dochtermann , Evan Haithcock , Joshua Marsh , Suho Oh , Anna Truman

In geometric analysis, an index theorem relates the difference of the numbers of solutions of two differential equations to the topological structure of the manifold or bundle concerned, sometimes using the heat kernels of two higher-order…

Spectral Theory · Mathematics 2009-11-13 S. A. Fulling , P. Kuchment , J. H. Wilson

Laplacian operators on finite compact metric graphs are considered under the assumption that matching conditions at graph vertices are of $\delta$ and $\delta'$ types. An infinite series of trace formulae is obtained which link together two…

Spectral Theory · Mathematics 2014-11-06 Yulia Ershova , Irina I. Karpenko , Alexander V. Kiselev

Let $G$ be a simple graph with the Laplacian matrix $L(G)$ and let $e(G)$ be the number of edges of $G$. A conjecture by Brouwer and a conjecture by Grone and Merris state that the sum of the $k$ largest Laplacian eigenvalues of $G$ is at…

Combinatorics · Mathematics 2018-09-13 Asghar Bahmani

Finite order invariants (Vassiliev invariants) of knots are expressed in terms of weight systems, that is, functions on chord diagrams satisfying the four-term relations. Weight systems have graph analogues, so-called $4$-invariants of…

Combinatorics · Mathematics 2018-06-01 V. I. Zhukov

A rose graph is a graph consisting of cycles that all meet in one vertex. We show that except for two specific examples, these rose graphs are determined by the Laplacian spectrum, thus proving a conjecture posed by Lui and Huang [F.J. Liu…

Combinatorics · Mathematics 2017-09-20 Changxiang He , Edwin R. van Dam

A unified approach to the determination of eigenvalues and eigenvectors of specific matrices associated with directed graphs is presented. Matrices studied include the distance matrix, distance Laplacian, and distance signless Laplacian, in…

Combinatorics · Mathematics 2020-08-04 Minerva Catral , Lorenzo Ciardo , Leslie Hogben , Carolyn Reinhart

Finding the stochastic equilibria for finite-state stochastic matrices amounts to solving an eigen\-vector problem $\pi = \pi P$. Various techniques for doing so are known, some extremely computationally intensive. Herein we shall aim to…

Mathematical Physics · Physics 2026-01-28 Matt Visser

Let $N(X)$ be the Laplacian matrix of a directed graph obtained from the edge adjacency matrix of a graph $X.$ In this work, we study the bipartiteness property of the graph with the help of $N(X).$ We computed the spectrum of the edge…

Combinatorics · Mathematics 2023-09-28 Shivani Chauhan , A. Satyanarayana Reddy

The complete knowledge of Laplacian eigenvalues and eigenvectors of complex networks plays an outstanding role in understanding various dynamical processes running on them; however, determining analytically Laplacian eigenvalues and…

Statistical Mechanics · Physics 2009-07-10 Zhongzhi Zhang , Yi Qi , Shuigeng Zhou , Yuan Lin , Jihong Guan

For a given infinite connected graph $G=(V,E)$ and an arbitrary but fixed conductance function $c$, we study an associated graph Laplacian $\Delta_{c}$; it is a generalized difference operator where the differences are measured across the…

Functional Analysis · Mathematics 2015-06-19 Palle Jorgensen , Feng Tian

We consider a non self-adjoint Laplacian on a directed graph with non symmetric weights on edges. We give a criterion for the m-accretiveness and the m-sectoriality of this Laplacian. Our results are based on a comparison of this operator…

Spectral Theory · Mathematics 2019-06-19 Colette Anné , Marwa Balti , Nabila Torki-Hamza

Riemann surfaces with nodes can be described by introducing simple composite operators in matrix models. In the case of the Kontsevich model, it is sufficient to add the quadratic, but ``non-propagating'', term (tr[X])^2 to the Lagrangian.…

High Energy Physics - Theory · Physics 2010-04-06 Damiano Anselmi

We give new general formulas for the asymptotics of the number of spanning trees of a large graph. A special case answers a question of McKay (1983) for regular graphs. The general answer involves a quantity for infinite graphs that we call…

Combinatorics · Mathematics 2010-04-27 Russell Lyons

This paper provides the generating series for the embedding of tree-like graphs of arbitrary number of vertices, accourding to their genus. It applies and extends the techniques of Chan, where it was used to give an alternate proof of the…

Combinatorics · Mathematics 2017-02-10 Aaron Chun Shing Chan