Results 101 to 110 of about 34,455 (233)
The Burning Number of Directed Graphs: Bounds and Computational Complexity
Theory and Applications of Graphs, 2020 The burning number of a graph was recently introduced by Bonato et al. Although they mention that the burning number generalizes naturally to directed graphs, no further research on this has been done. Here, we introduce graph burning for directed graphs,
Remie Janssen
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On the Cayley digraphs that are patterns of unitary matrices
, 2002 A digraph D is the pattern of a matrix M when D has an arc ij if and only if the ij-th entry of M is nonzero. Study the relationship between unitary matrices and their patterns is motivated by works in quantum chaology and quantum computation.
Severini, Simone
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Journal of Graph Theory, Volume 110, Issue 1, Page 82-91, September 2025.ABSTRACT An inversion of a tournament T is obtained by reversing the direction of all edges with both endpoints in some set of vertices. Let inv k ( T ) be the minimum length of a sequence of inversions using sets of size at most k that result in the transitive tournament.
Raphael Yuster
wiley +1 more source
Tr-Span of Directed Wheel Graphs
Discussiones Mathematicae Graph Theory, 2018 In this paper, we consider T-colorings of directed graphs. In particular, we consider as a T-set the set Tr = {0, 1, 2, . . ., r−1, r+1, . . .}. Exact values and bounds of the Tr-span of directed graphs whose underlying graph is a wheel graph are ...
Besson Marc, Tesman Barry
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On quotient digraphs and voltage digraphs
, 2016 In this note we present a general approach to construct large digraphs from small ones. These are called expanded digraphs, and, as particular cases, we show their close relationship between voltage digraphs and line digraphs, which are two known approaches to obtain dense digraphs.
Dalfó Simó, Cristina +3 more
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European Journal of Combinatorics, 2006 AbstractWe consider a directed version of Deza graphs. A digraph is said to be a Deza digraph if it is regular and the number of common out-neighbors of any two distinct vertices takes on at most two values. We introduce some constructions and develop some basic theory.
Yan-Quan Feng, Kaishun Wang
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An Exact Algorithm for the Hazardous Orienteering Problem
Networks, Volume 86, Issue 2, Page 105-111, September 2025.ABSTRACT The hazardous orienteering problem is the topic of this study. It is a variant of the well‐studied orienteering problem, where a vehicle, given a maximum mission time, has to select and visit customers out of a set of requests, aiming at maximizing the total profit associated with the customers selected. In the hazardous version of the problem
Roberto Montemanni, Derek H. Smith
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Unordered Love in infinite directed graphs
International Journal of Mathematics and Mathematical Sciences, 1992 A digraph D=(V,A) has the Unordered Love Property (ULP) if any two different vertices have a unique common outneighbor. If both (V,A) and (V,A−1) have the ULP, we say that D has the SDULP.
Peter D. Johnson
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Journal of Combinatorial Theory, Series B, 1973 AbstractLet c(x,y) denote the maximum number of edge-disjoint directed paths joining x to y in the digraph G. It is shown that, for a given point a of G, c(a,x) ≤ c(x,a) for any x implies that the outdegree of a is ≤ its indegree. An immediate consequence is Kotzig's conjecture: Given a digraph G, c(x,y) = c(y,x) for every x, y if and only if the graph
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Communications in Combinatorics and Optimization, 2016 Let $D$ be a finite and simple digraph with vertex set $V(D)$. For a vertex $v\in V(D)$, the degree of $v$, denoted by $d(v)$, is defined as the minimum value of its out-degree $d^+(v)$ and its in-degree $d^-(v)$.
L. Volkmann
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