Results 1 to 10 of about 771 (82)

On Antipodal and Diametrical Partial Cubes

open access: yesDiscussiones Mathematicae Graph Theory, 2021
We prove that any diametrical partial cube of diameter at most 6 is antipodal. Because any antipodal graph is harmonic, this gives a partial answer to a question of Fukuda and Handa [Antipodal graphs and oriented matroids, Discrete Math.
Polat Norbert
doaj   +1 more source

A Constructive Characterization of Vertex Cover Roman Trees

open access: yesDiscussiones Mathematicae Graph Theory, 2021
A Roman dominating function on a graph G = (V (G), E(G)) is a function f : V (G) → {0, 1, 2} satisfying the condition that every vertex u for which f (u) = 0 is adjacent to at least one vertex v for which f (v) = 2.
Martínez Abel Cabrera   +2 more
doaj   +1 more source

Dualizing Distance-Hereditary Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2021
Distance-hereditary graphs can be characterized by every cycle of length at least 5 having crossing chords. This makes distance-hereditary graphs susceptible to dualizing, using the common extension of geometric face/vertex planar graph duality to cycle ...
McKee Terry A.
doaj   +1 more source

Capture-Time Extremal Cop-Win Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2021
We investigate extremal graphs related to the game of Cops and Robbers. We focus on graphs where a single cop can catch the robber; such graphs are called cop-win.
Offner David, Ojakian Kerry
doaj   +1 more source

Covering the Edges of a Random Hypergraph by Cliques

open access: yesDiscussiones Mathematicae Graph Theory, 2022
We determine the order of magnitude of the minimum clique cover of the edges of a binomial, r-uniform, random hypergraph G(r)(n, p), p fixed. In doing so, we combine the ideas from the proofs of the graph case (r = 2) in Frieze and Reed [Covering the ...
Rödl Vojtěch, Ruciński Andrzej
doaj   +1 more source

Convergence of Laplacians on smooth spaces towards the fractal Sierpiński gasket

open access: yes, 2020
The purpose of this article is to prove that – under reasonable assumptions – the canonical energy form on a graph-like manifold is quasi-unitarily equivalent with the energy form on the underlying discrete graph.
O. Post, J. Simmer
semanticscholar   +1 more source

A Spectral Characterization of the S-Clique Extension of the Triangular Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2020
A regular graph is co-edge regular if there exists a constant µ such that any two distinct and non-adjacent vertices have exactly µ common neighbors. In this paper, we show that for integers s ≥ 2 and n large enough, any co-edge-regular graph which is ...
Tan Ying-Ying   +2 more
doaj   +1 more source

On Proper (Strong) Rainbow Connection of Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2021
A path in an edge-colored graph G is called a rainbow path if no two edges on the path have the same color. The graph G is called rainbow connected if between every pair of distinct vertices of G, there is a rainbow path.
Jiang Hui   +3 more
doaj   +1 more source

A Note on Quasi-Triangulated Graphs [PDF]

open access: yes, 2006
A graph is quasi-triangulated if each of its induced subgraphs has a vertex which is either simplicial (its neighbors form a clique) or cosimplicial (its nonneighbors form an independent set).
Gorgos, Ion   +2 more
core   +2 more sources

On the Existence of General Factors in Regular Graphs [PDF]

open access: yes, 2012
Let $G$ be a graph, and $H\colon V(G)\to 2^\mathbb{N}$ a set function associated with $G$. A spanning subgraph $F$ of $G$ is called an $H$-factor if the degree of any vertex $v$ in $F$ belongs to the set $H(v)$.
Lu, Hongliang   +2 more
core   +1 more source

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