English
Related papers

Related papers: New constructions of Deza digraphs

200 papers

We show that every graph with twin-width $t$ has chromatic number $O(\omega ^{k_t})$ for some integer $k_t$, where $\omega$ denotes the clique number. This extends a quasi-polynomial bound from Pilipczuk and Soko{\l}owski and generalizes a…

Discrete Mathematics · Computer Science 2025-01-20 Romain Bourneuf , Stéphan Thomassé

\emph{Bidirected graphs} (a sort of nonstandard graphs introduced by Edmonds and Johnson) provide a natural generalization to the notions of directed and undirected graphs. By a \emph{weakly (node- or edge-) acyclic} bidirected graph we…

Combinatorics · Mathematics 2007-05-23 Maxim A. Babenko

Two-sided group digraphs and graphs, introduced by Iradmusa and Praeger, provide a generalization of Cayley digraphs and graphs in which arcs are determined by left and right multiplying by elements of two subsets of the group. We…

Combinatorics · Mathematics 2018-04-04 Patreck Chikwanda , Cathy Kriloff , Yun Teck Lee , Taylor Sandow , Garrett Smith , Dmytro Yeroshkin

If $(\omega(e))$ is a family of random variables (weights) assigned to the edges of $\mathbb{Z}^d$, the nearest neighbor graph is the directed graph induced by all edges $\langle x,y \rangle$ such that $\omega(\{x,y\})$ is minimal among all…

Probability · Mathematics 2020-07-01 Bounghun Bock , Michael Damron , Jack Hanson

We introduce a generalization of the zig-zag product of regular digraphs (directed graphs), which allows us to construct regular digraphs with m ore flexible choices of the degrees. In our generalization, we can control the connectivity of…

Probability · Mathematics 2007-05-23 Shunichi Nomura , Akimichi Takemura

Etzion et al. introduced metrics on $\mathbb{F}_2^n$ based on directed graphs on $n$ vertices and developed some basic coding theory on directed graph metric spaces. In this paper, we consider the problem of classifying directed graphs…

Combinatorics · Mathematics 2017-03-02 Jong Yoon Hyun , Hyun Kwang Kim , Jeong Rye Park

Assume that $\nu$ is a positive integer and $\delta=0, 1$ or $2$. In this paper we introduce the orthogonal graph $\Gamma^{2\nu+\delta}$ over a Galois ring of odd characteristic and prove that it is arc transitive. Moreover, we compute its…

Combinatorics · Mathematics 2013-08-20 Fenggao Li , Jun Guo , Kaishun Wang

We propose a classification of polyhedra (planar, $3$-connected graphs) according to their type i.e., their set of quantities of common neighbours for each pair of distinct vertices. For every (finite) set of non-negative integers, we…

Combinatorics · Mathematics 2025-08-05 Riccardo W. Maffucci

We revisit the concepts of acyclic orderings and number of acyclic orderings of acyclic digraphs in terms of dispositions and counters for arbitrary multidigraphs. We prove that when we add a sequence of nested directed paths to a directed…

A $\overrightarrow{P_{3}}$-decomposition of a directed graph $D$ is a partition of the arcs of $D$ into directed paths of length $2$. In this paper, we give a characterization for a tournament and a bipartite digraph admitting a…

Combinatorics · Mathematics 2016-11-11 Fangxia Wang , Baoyindureng Wu , Xinhui An

Here I report about the modifications of and relations between graphic lambda calculus, various formalisms which appeared under the name chemlambda and a version of directed interaction combinators. This is part of the study and experiments…

Logic in Computer Science · Computer Science 2020-07-21 Marius Buliga

In this survey we overview known results and get several new results on digraph compositions which generalize several classes of digraphs, such as quasi-transitive digraphs. After an introductory section, the paper is divided into six…

Combinatorics · Mathematics 2023-06-16 Yuefang Sun

We present the first comprehensive analysis of temporal settings for directed temporal graphs, fully resolving their hierarchy with respect to support, reachability, and induced-reachability equivalence. These notions, introduced by…

Discrete Mathematics · Computer Science 2025-01-22 Michelle Döring

We define and investigate properties of universal operator algebras of directed graphs. Results include free products decomposition and continuity of the construction with respect to direct limits. Lastly we prove some K-theoretic results…

Operator Algebras · Mathematics 2007-05-23 Benton L. Duncan

String diagrams are a powerful tool for reasoning about physical processes, logic circuits, tensor networks, and many other compositional structures. Dixon, Duncan and Kissinger introduced string graphs, which are a combinatoric…

Category Theory · Mathematics 2014-04-02 Aleks Kissinger , Alex Merry , Matvey Soloviev

A regular-graph design is a block design for which a pair $\{a,b\}$ of distinct points occurs in $\lambda+1$ or $\lambda$ blocks depending on whether $\{a,b\}$ is or is not an edge of a given $\delta$-regular graph. Our paper describes a…

Combinatorics · Mathematics 2025-01-14 Anthony Forbes , Carrie Rutherford

We recently introduced a formalism for the modeling of temporal networks, that we call stream graphs. It emphasizes the streaming nature of data and allows rigorous definitions of many important concepts generalizing classical graphs. This…

Social and Information Networks · Computer Science 2021-11-24 Matthieu Latapy , Clémence Magnien , Tiphaine Viard

Inspired by a width invariant on permutations defined by Guillemot and Marx, Bonnet, Kim, Thomass\'e, and Watrigant introduced the twin-width of graphs, which is a parameter describing its structural complexity. This invariant has been…

Logic in Computer Science · Computer Science 2024-08-07 Édouard Bonnet , Jaroslav Nešetřil , Patrice Ossona de Mendez , Sebastian Siebertz , Stéphan Thomassé

Many interesting examples of operator algebras, both self-adjoint and non-self-adjoint, can be constructed from directed graphs. In this survey, we overview the construction of $C^*$-algebras from directed graphs and from two…

Operator Algebras · Mathematics 2022-09-07 Juliana Bukoski , Sushil Singla

The arc graph $\delta(G)$ of a digraph $G$ is the digraph with the set of arcs of $G$ as vertex-set, where the arcs of $\delta(G)$ join consecutive arcs of $G$. In 1981, Poljak and R\"{o}dl characterised the chromatic number of $\delta(G)$…

Combinatorics · Mathematics 2016-10-06 Danny Rorabaugh , Claude Tardif , David Wehlau , Imed Zaguia