Results 61 to 70 of about 834 (84)

Bounds on the Signed Roman k-Domination Number of a Digraph

Discussiones Mathematicae Graph Theory, 2019
Let k be a positive integer. A signed Roman k-dominating function (SRkDF) on a digraph D is a function f : V (D) → {−1, 1, 2} satisfying the conditions that (i) Σx∈N−[v]f(x) ≥ k for each v ∈ V (D), where N−[v] is the closed in-neighborhood of v, and (ii)
Chen Xiaodan, Hao Guoliang, Volkmann Lutz   +2 more
doaj   +1 more source

Some Results on 4-Transitive Digraphs

Discussiones Mathematicae Graph Theory, 2017
Let D be a digraph with set of vertices V and set of arcs A. We say that D is k-transitive if for every pair of vertices u, v ∈ V, the existence of a uv-path of length k in D implies that (u, v) ∈ A.
García-Vázquez Patricio Ricardo, Hernández-Cruz César   +1 more
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Super Edge-Connectivity and Zeroth-Order Randić Index

Discussiones Mathematicae Graph Theory, 2020
Define the zeroth-order Randić index as R0(G)=∑x∈V(G)1dG(x),{R^0}\left( G \right) = \sum\nolimits_{x \in V\left( G \right)} {{1 \over {\sqrt {{d_G}} \left( x \right)}},} where dG(x) denotes the degree of the vertex x.
He Zhihong, Lu Mei
doaj   +1 more source

𝕮-inverse of graphs and mixed graphs

Open Mathematics
This article introduces a generalization of the concept of inverse graphs applicable to both graphs and mixed graphs. Given a graph GG with adjacency matrix A(G)A\left(G), the inverse graph G−1{G}^{-1} is defined such that its adjacency matrix is similar
Alomari Omar, Abudayah Mohammad, Ghanem Manal   +2 more
doaj   +1 more source

γ-Inverse graph of some mixed graphs

Special Matrices
Let GG be a graph. Then, the inverse graph G−1{G}^{-1} of GG is defined to be a graph that has adjacency matrix similar to the inverse of the adjacency matrix of GG, where the similarity matrix is ±1\pm 1 diagonal matrix. In this article, we introduced a
Boulahmar Wafa, Ghanem Manal, Abudayah Mohammad   +2 more
doaj   +1 more source

Causal structure learning in directed, possibly cyclic, graphical models

Journal of Causal Inference
We consider the problem of learning a directed graph G⋆{G}^{\star } from observational data. We assume that the distribution that gives rise to the samples is Markov and faithful to the graph G⋆{G}^{\star } and that there are no unobserved variables.
Semnani Pardis, Robeva Elina
doaj   +1 more source

Complete graphs: the space of simplicial cones, and their path tree representation

, 2017
Let $G$ be a complete graph with $n+1$ vertices. In a recent paper of the authors, it is shown that the path trees of the graph play a special role in the structure of the truncated powers and partition functions that are associated with the graph ...
Ron, Amos, Shengnan, Wang
core  

γ-Cycles In Arc-Colored Digraphs

Discussiones Mathematicae Graph Theory, 2016
We call a digraph D an m-colored digraph if the arcs of D are colored with m colors. A directed path (or a directed cycle) is called monochromatic if all of its arcs are colored alike.
Galeana-Sánchez Hortensia, Gaytán-Gómez Guadalupe, Rojas-Monroy Rocío   +2 more
doaj   +1 more source

Sub-exponential Time Parameterized Algorithms for Graph Layout Problems on Digraphs with Bounded Independence Number. [PDF]

Algorithmica, 2023
Misra P, Saurabh S, Sharma R, Zehavi M.
europepmc   +1 more source

A branch-and-cut algorithm for the target visitation problem

EURO Journal on Computational Optimization, 2019
In this paper, we consider the target visitation problem (TVP) which arises in the context of disaster treatment. Mathematically speaking, the problem is concerned with finding a route to visit a set of targets starting from and returning to some base ...
Achim Hildenbrandt
doaj   +1 more source