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A $k$-bisection of a bridgeless cubic graph $G$ is a $2$-colouring of its vertex set such that the colour classes have the same cardinality and all connected components in the two subgraphs induced by the colour classes (monochromatic…

Combinatorics · Mathematics 2018-09-11 Marien Abreu , Jan Goedgebeur , Domenico Labbate , Giuseppe Mazzuoccolo

The graph reconstruction conjecture asserts that every simple graph on at least three vertices is uniquely determined by its deck of vertex-deleted subgraphs. In this expository article we survey the conjecture and present an…

Combinatorics · Mathematics 2026-04-21 Emilie Dufresne , Gabriela Jeronimo , Jenny Kenkel , Haydee Lindo , Nelly Villamizar

Let $G_{g,b}$ be the set of all uni/trivalent graphs representing the combinatorial structures of pant decompositions of the oriented surface of genus $g$ with $b$ boundary components. We describe the set $A_{g,b}$ of all automorphisms of…

Geometric Topology · Mathematics 2011-11-16 Silvia Benvenuti , Riccardo Piergallini

Given a connected graph G with p vertices and q edges, the G-graphicahedron is a vertex-transitive simple abstract polytope of rank q whose edge-graph is isomorphic to a Cayley graph of the symmetric group S_p associated with G. The paper…

Combinatorics · Mathematics 2012-06-26 Maria Del Rio-Francos , Isabel Hubard , Deborah Oliveros , Egon Schulte

We give a general construction leading to different non-isomorphic families $\Gamma_{n,q}(\K)$ of connected $q$-regular semisymmetric graphs of order $2q^{n+1}$ embedded in $\PG(n+1,q)$, for a prime power $q=p^h$, using the linear…

Combinatorics · Mathematics 2013-01-10 Philippe Cara , Sara Rottey , Geertrui Van de Voorde

Inspired by the study of community structure in connection networks, we introduce the graph polynomial $Q(G;x,y)$, the bivariate generating function which counts the number of connected components in induced subgraphs. We give a recursive…

Combinatorics · Mathematics 2013-09-10 P. Tittmann , I. Averbouch , J. A. Makowsky

Let $G$ be a unicyclic graph of order $n$, and let $k$ be the length of the unique cycle of $G$. For the adjacency eigenvalues of $G$, let $s^{+}(G)$ and $s^{-}(G)$ denote the sums of the squares of the positive and negative eigenvalues,…

Combinatorics · Mathematics 2026-05-26 Bo Ning , Jing Zeng

We consider 3 (weighted) posets associated with a graph G - the poset P(G) of distinct induced unlabelled subgraphs, the lattice Omega(G) of distinct unlabelled graphs induced by connected partitions, and the poset Q(G) of distinct…

Combinatorics · Mathematics 2015-08-19 Bhalchandra D. Thatte

In [{Structural properties and decomposition of linear balanced matrices}, {\it Mathematical Programming}, 55:129--168, 1992], Conforti and Rao conjectured that every balanced bipartite graph contains an edge that is not the unique chord of…

A graph is well-covered if all its maximal independent sets are of the same cardinality (Plummer, 1970). If G is a well-covered graph, has at least two vertices, and G-v is well-covered for every vertex v, then G is a 1-well-covered graph…

Combinatorics · Mathematics 2016-12-13 Vadim E. Levit , Eugen Mandrescu

Given a function $f$ in a finite field ${\mathbb F}_q$ of $q$ elements, we define the functional graph of $f$ as a directed graph on $q$ nodes labelled by the elements of ${\mathbb F}_q$ where there is an edge from $u$ to $v$ if and only if…

Number Theory · Mathematics 2015-05-27 Sergei V. Konyagin , Florian Luca , Bernard Mans , Luke Mathieson , Min Sha , Igor E. Shparlinski

As a variant of the Ulam's vertex reconstruction conjecture and the Harary's edge reconstruction conjecture, Cvetkovi\'c and Schwenk posed independently the following problem: Can the characteristic polynomial of a simple graph $G$ with…

Combinatorics · Mathematics 2023-10-12 Jingyuan Zhang , Xian'an Jin , Weigen Yan , Qinghai Liu

In this work we consider the class of Cayley graphs known as generalized Paley graphs (GP-graphs for short) given by $\Gamma(k,q) = Cay(\mathbb{F}_q, \{x^k : x\in \mathbb{F}_q^* \})$, where $\mathbb{F}_q$ is a finite field with $q$…

Combinatorics · Mathematics 2025-04-03 Ricardo A. Podestá , Denis E. Videla

In this paper, we prove a tight minimum degree condition in general graphs for the existence of paths between two given endpoints, whose lengths form a long arithmetic progression with common difference one or two. This allows us to obtain…

Combinatorics · Mathematics 2021-01-27 Jun Gao , Qingyi Huo , Chun-Hung Liu , Jie Ma

We consider the issue of when the L-polynomial of one curve over $\F_q$ divides the L-polynomial of another curve. We prove a theorem which shows that divisibility follows from a hypothesis that two curves have the same number of points…

Number Theory · Mathematics 2014-10-01 Omran Ahmadi , Gary McGuire , Antonio Rojas-León

We give an especially simple proof of a theorem in graph theory that forms the key part of the solution to a problem in commutative algebra, on how to characterize the integral closure of a polynomial ring generated by quadratic monomials.

Commutative Algebra · Mathematics 2011-06-09 Peter M. Johnson

The paper contains a proof of the conjecture of M. Klin and D. Maru$\breve{\rm s}$i$\breve{\rm c}$ that an automorphism group of a transitive graph contains a permutation, decomposed in cycles of the same length. The proof is based on the…

General Mathematics · Mathematics 2007-05-23 Aleksandr Golubchik

Given two subgroups $H,K$ of a finite group $G$, the probability that a pair of random elements from $H$ and $K$ commutes is denoted by $Pr(H,K)$. Suppose that a finite group $G$ admits a group of coprime automorphisms $A$ and let…

Group Theory · Mathematics 2025-11-12 Eloisa Detomi , Robert M. Guralnick , Marta Morigi , Pavel Shumyatsky

Let $G$ be a bipartite graph with adjacency matrix $A(G)$. The characteristic polynomial $\phi(G,x)=\det(xI-A(G))$ and the permanental polynomial $\pi(G,x) = \text{per}(xI-A(G))$ are both graph invariants used to distinguish graphs. For…

Combinatorics · Mathematics 2024-11-22 Ravindra B. Bapat , Ranveer Singh , Hitesh Wankhede

Let $f=a\x+\x^{3q-2}\in\Bbb F_{q^2}[\x]$, where $a\in\Bbb F_{q^2}^*$. We prove that $f$ is a permutation polynomial of $\Bbb F_{q^2}$ if and only if one of the following occurs: (i) $q=2^e$, $e$ odd, and $a^{\frac{q+1}3}$ is a primitive…

Number Theory · Mathematics 2013-12-24 Xiang-dong Hou , Stephen D. Lappano