Results 11 to 20 of about 730 (67)

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

On the edge set of graphs of lattice paths

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 2004, Issue 61, Page 3291-3299, 2004., 2004
This note explores a new family of graphs defined on the set of paths of the m × n lattice. We let each of the paths of the lattice be represented by a vertex, and connect two vertices by an edge if the corresponding paths share more than k steps, where k is a fixed parameter 0 = k = m + n. Each such graph is denoted by G(m, n, k).
Steven Klee, Lara Pudwell, Rick Gillman
wiley   +1 more source

On Accurate Domination in Graphs

open access: yesDiscussiones Mathematicae Graph Theory, 2019
A dominating set of a graph G is a subset D ⊆ VG such that every vertex not in D is adjacent to at least one vertex in D. The cardinality of a smallest dominating set of G, denoted by γ(G), is the domination number of G. The accurate domination number of
Cyman Joanna   +2 more
doaj   +1 more source

Minimally Strong Subgraph (k,ℓ)-Arc-Connected Digraphs

open access: yesDiscussiones Mathematicae Graph Theory, 2022
Let D = (V,A) be a digraph of order n, S a subset of V of size k and 2 ≤ k ≤ n. A subdigraph H of D is called an S-strong subgraph if H is strong and S ⊆ V (H). Two S-strong subgraphs D1 and D2 are said to be arc-disjoint if A(D1) ∩ A(D2) = ∅.
Sun Yuefang, Jin Zemin
doaj   +1 more source

Old and new generalizations of line graphs

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 2004, Issue 29, Page 1509-1521, 2004., 2004
Line graphs have been studied for over seventy years. In 1932, H. Whitney showed that for connected graphs, edge‐isomorphism implies isomorphism except for K3 and K1,3. The line graph transformation is one of the most widely studied of all graph transformations.
Jay Bagga
wiley   +1 more source

Characterizing symmetric diametrical graphs of order 12 and diameter 4

open access: yesInternational Journal of Mathematics and Mathematical Sciences, Volume 30, Issue 3, Page 145-149, 2002., 2002
A diametrical graph G is said to be symmetric if d(u,v)+d(v,u¯)=d(G) for all u, v ∈ V(G), where u¯ is the buddy of u. If moreover, G is bipartite, then it is called an S‐graph. It would be shown that the Cartesian product K2 × C6 is not only the unique S‐graph of order 12 and diameter 4, but also the unique symmetric diametrical graph of order 12 and ...
S. Al-Addasi, H. Al-Ezeh
wiley   +1 more source

Existence of Regular Nut Graphs for Degree at Most 11

open access: yesDiscussiones Mathematicae Graph Theory, 2020
A nut graph is a singular graph with one-dimensional kernel and corresponding eigenvector with no zero elements. The problem of determining the orders n for which d-regular nut graphs exist was recently posed by Gauci, Pisanski and Sciriha.
Fowler Patrick W.   +4 more
doaj   +1 more source

Characterizing Atoms that Result from Decomposition by Clique Separators

open access: yesDiscussiones Mathematicae Graph Theory, 2017
A graph is defined to be an atom if no minimal vertex separator induces a complete subgraph; thus, atoms are the graphs that are immune to clique separator decomposition.
McKee Terry A.
doaj   +1 more source

On Some Properties of Antipodal Partial Cubes

open access: yesDiscussiones Mathematicae Graph Theory, 2020
We prove that an antipodal bipartite graph is a partial cube if and only it is interval monotone. Several characterizations of the principal cycles of an antipodal partial cube are given.
Polat Norbert
doaj   +1 more source

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