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A trivalent diagram is a connected, two-colored bipartite graph (parallel edges allowed but not loops) such that every black vertex is of degree 1 or 3 and every white vertex is of degree 1 or 2, with a cyclic order imposed on every set of…

Combinatorics · Mathematics 2012-01-31 Samuel Alexandre Vidal

The class of $\mathsf{Ga}$lled-$\mathsf{T}$ree $\mathsf{Ex}$plainable ($\mathsf{GaTEx}$) graphs has recently been discovered as a natural generalization of cographs. Cographs are precisely those graphs that can be uniquely represented by a…

Discrete Mathematics · Computer Science 2024-04-29 Marc Hellmuth , Guillaume E. Scholz

We present novel graph kernels for graphs with node and edge labels that have ordered neighborhoods, i.e. when neighbor nodes follow an order. Graphs with ordered neighborhoods are a natural data representation for evolving graphs where…

Machine Learning · Computer Science 2018-05-30 Moez Draief , Konstantin Kutzkov , Kevin Scaman , Milan Vojnovic

Iterated loop algebras are by definition obtained by repeatedly applying the loop construction, familiar from the theory of affine Kac-Moody Lie algebras, to a given base algebra. Our interest in this iterated construction is motivated by…

Representation Theory · Mathematics 2008-09-06 Bruce Allison , Stephen Berman , Arturo Pianzola

In phylogenetics, evolution is traditionally represented in a tree-like manner. However, phylogenetic networks can be more appropriate for representing evolutionary events such as hybridization, horizontal gene transfer, and others. In…

Data Structures and Algorithms · Computer Science 2024-10-18 Manuel Lafond , Vincent Moulton

Graph polynomials are polynomials assigned to graphs. Interestingly, they also arise in many areas outside graph theory as well. Many properties of graph polynomials have been widely studied. In this paper, we survey some results on the…

Combinatorics · Mathematics 2016-01-13 Xueliang Li , Yongtang Shi

We enumerate rooted 2-connected and 3-connected surface maps with respect to vertices and edges. We also derive the bivariate version of the large face-width result for random 3-connected maps. These results are then used to derive…

Combinatorics · Mathematics 2010-03-16 E. A. Bender , Z. Gao

The class ${\cal L}_k$ of $k$-leaf powers consists of graphs $G=(V,E)$ that have a $k$-leaf root, that is, a tree $T$ with leaf set $V$, where $xy \in E$, if and only if the $T$-distance between $x$ and $y$ is at most $k$. Structure and…

Discrete Mathematics · Computer Science 2014-02-07 Ragnar Nevries , Christian Rosenke

The literature on word-representable graphs is quite rich, and a number of variations of the original definition have been proposed over the years. We are initiating a systematic study of such variations based on formal languages. In our…

Discrete Mathematics · Computer Science 2024-11-06 Zhidan Feng , Henning Fernau , Pamela Fleischmann , Kevin Mann , Silas Cato Sacher

We show that the large Cartesian powers of any graph have log-concave valencies with respect to a ffxed vertex. We show that the series of valencies of distance regular graphs is log-concave, thus improving on a result of (Taylor,…

Combinatorics · Mathematics 2025-01-22 Minjia Shi , Lu Wang , Patrick Sole

In this article, we study the properties of profinite geometric iterated monodromy groups associated to polynomials. Such groups can be seen as generic representations of absolute Galois groups of number fields into the automorphism group…

Dynamical Systems · Mathematics 2025-07-08 Mikhail Hlushchanka , Olga Lukina , Dean Wardell

An embedding of a graph on an orientable surface is orientably-regular (or rotary, in an equivalent terminology) if the group of orientation-preserving automorphisms of the embedding is transitive (and hence regular) on incident vertex-edge…

Combinatorics · Mathematics 2023-11-17 Stefan Gyurki , Sona Pavlikova , Jozef Siran

We consider the problem of graph generation guided by network statistics, i.e., the generation of graphs which have given values of various numerical measures that characterize networks, such as the clustering coefficient and the number of…

Social and Information Networks · Computer Science 2023-03-02 Jérôme Kunegis , Jun Sun , Eiko Yoneki

We prove that wheels and block graphs have sequentially Cohen-Macaulay binomial edge ideals. Moreover, we provide a construction of new families of sequentially Cohen-Macaulay graphs by cones.

Commutative Algebra · Mathematics 2025-07-08 Ernesto Lax , Giancarlo Rinaldo , Francesco Romeo

A graph is called (claw,diamond)-free if it contains neither a claw (a $K_{1,3}$) nor a diamond (a $K_4$ with an edge removed) as an induced subgraph. Equivalently, (claw,diamond)-free graphs can be characterized as line graphs of…

Data Structures and Algorithms · Computer Science 2015-03-03 Marek Cygan , Marcin Pilipczuk , Michał Pilipczuk , Erik Jan van Leeuwen , Marcin Wrochna

We give an explicit combinatorial proof of a weighted version of strong log-concavity for the generating polynomial of increasing spanning forests of a finite simple graph equipped with a total ordering of the vertices. In contrast to…

Combinatorics · Mathematics 2021-01-13 Abdelmalek Abdesselam

We raise some questions about graph polynomials, highlighting concepts and phenomena that may merit consideration in the development of a general theory. Our questions are mainly of three types: When do graph polynomials have reduction…

Combinatorics · Mathematics 2024-06-25 Graham Farr , Kerri Morgan

In the realm of generative models for graphs, extensive research has been conducted. However, most existing methods struggle with large graphs due to the complexity of representing the entire joint distribution across all node pairs and…

Social and Information Networks · Computer Science 2024-05-15 Andreas Bergmeister , Karolis Martinkus , Nathanaël Perraudin , Roger Wattenhofer

Let $G$ be a simple graph and $I(G)$ be its edge ideal. In this article, we study the Castelnuovo-Mumford regularity of symbolic powers of edge ideals of join of graphs. As a consequence, we prove Minh's conjecture for wheel graphs,…

Commutative Algebra · Mathematics 2020-08-04 Arvind Kumar , Rajiv Kumar , Rajib Sarkar

Suppose that $G_j$ is a sequence of finite connected planar graphs, and in each $G_j$ a special vertex, called the root, is chosen randomly-uniformly. We introduce the notion of a distributional limit $G$ of such graphs. Assume that the…

Probability · Mathematics 2008-11-26 Itai Benjamini , Oded Schramm