Results 21 to 30 of about 208,933 (266)

Directed triangles in directed graphs

Discrete Mathematics, 1992
The authors show that if each vertex of an oriented graph \(G_ n\) has indegree and outdegree at least \(n/t\), where \(t=2.867\dots,\) then \(G_ n\) contains an oriented 3-cycle.
Maurits de Graaf, Alexander Schrijver, Paul D. Seymour   +2 more
openaire   +3 more sources

Asteroidal Quadruples in non Rooted Path Graphs

Discussiones Mathematicae Graph Theory, 2015
A directed path graph is the intersection graph of a family of directed subpaths of a directed tree. A rooted path graph is the intersection graph of a family of directed subpaths of a rooted tree. Rooted path graphs are directed path graphs.
Gutierrez Marisa, Lévêque Benjamin, Tondato Silvia B.   +2 more
doaj   +1 more source

Incidence Matrices of Directed Graphs of Groups and their up-down Pregroups

Sultan Qaboos University Journal for Science, 2017
The aim of this work is to give a definition of the incidence matrices of the directed graph of groups, construct an up-down pregroup of the incidence matrices of the directed graph of groups and then give an algorithm for the up-down pregroup of the ...
Wadhah S. Jassim
doaj   +1 more source

Extrema property of the k-ranking of directed paths and cycles

AKCE International Journal of Graphs and Combinatorics, 2016
A k-ranking of a directed graph G is a labeling of the vertex set of G with k positive integers such that every directed path connecting two vertices with the same label includes a vertex with a larger label in between.
Breeanne Baker Swart, Rigoberto Flórez, Darren A. Narayan, George L. Rudolph   +3 more
doaj   +1 more source

A Heuristic for Direct Product Graph Decomposition

Journal of Graph Algorithms and Applications, 2023
In this paper we describe a heuristic for decomposing a directed graph into factors according to the direct product (also known as Kronecker, cardinal or tensor product). Given a directed, unweighted graph $G$ with adjacency matrix $\mathbf{Adj}(G)$, our
Luca Calderoni, Luciano Margara, Moreno Marzolla   +2 more
doaj   +1 more source

Line graphs of directed graphs. I. [PDF]

Transactions on Combinatorics
Summary: We determine the forbidden induced subgraphs for the intersection of the classes of chordal bipartite graphs and line graphs of acyclic directed graphs. This is a first step towards finding the forbidden induced subgraphs for the class of line graphs of directed graphs.
Sivaraman, Vaidy, Slilaty, Daniel
openaire   +4 more sources

On Lossy Compression of Directed Graphs [PDF]

IEEE Transactions on Information Theory, 2022
Accepted for publication in IEEE Transactions on Information ...
Ronit Bustin, Ofer Shayevitz
openaire   +2 more sources

The Reduction of Directed Cyclic Graph for Task Assignment Problem

MATEC Web of Conferences, 2018
In this paper, a directed cyclic graph (DCG) is proposed as the task graph. It is undesirable and impossible to complete the task according to the constraints if the cycle exists.
Ariffin W.N.M.
doaj   +1 more source

Large-Scale Dynamic Social Network Directed Graph K-In&Out-Degree Anonymity Algorithm for Protecting Community Structure

IEEE Access, 2019
Social network data publishing is dynamic, and attackers can perform association attacks based on social network directed graph data at different times.
Xiaolin Zhang, Jiao Liu, Jian Li, Lixin Liu   +3 more
doaj   +1 more source

Hitting minors, subdivisions, and immersions in tournaments [PDF]

Discrete Mathematics & Theoretical Computer Science, 2018
The Erd\H{o}s-P\'osa property relates parameters of covering and packing of combinatorial structures and has been mostly studied in the setting of undirected graphs.
Jean-Florent Raymond
doaj   +1 more source