Results 61 to 70 of about 174 (114)
Journal of Mathematics, Volume 2024, Issue 1, 2024.Symmetry properties are of vital importance for graphs. The famous Cayley graph is a good mathematical model as its high symmetry. The normality of the graph can well reflect the symmetry of the graph. In this paper, we characterize the normality of the direct product of Cayley graphs and give a sufficient and necessary condition for the direct product
Li Wang +3 more
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The Planar Index and Outerplanar Index of Some Graphs Associated to Commutative Rings
Discussiones Mathematicae - General Algebra and Applications, 2019 In this paper, we study the planar and outerplanar indices of some graphs associated to a commutative ring. We give a full characterization of these graphs with respect to their planar and outerplanar indices when R is a finite ring.
Barati Zahra, Afkhami Mojgan
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Pentavalent arc-transitive Cayley graphs on Frobenius groups with soluble vertex stabilizer
Open Mathematics, 2019 A Cayley graph Γ is said to be arc-transitive if its full automorphism group AutΓ is transitive on the arc set of Γ. In this paper we give a characterization of pentavalent arc-transitive Cayley graphs on a class of Frobenius groups with soluble vertex ...
Liu Hailin
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Simplicial complexes defined on groups
Open MathematicsThis study makes some preliminary observations towards an extension of current work on graphs defined on groups to simplicial complexes. I define a variety of simplicial complexes on a group, which are preserved by automorphisms of the group, and in many
Cameron Peter J.
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Note on the product of the largest and the smallest eigenvalue of a graph
Special MatricesIn this note, we use eigenvalue interlacing to derive an inequality between a graph’s maximum degree and its maximum and minimum adjacency eigenvalues. The equality case is fully characterized.
Abiad Aida +2 more
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2-closures of primitive permutation groups of holomorph type
Open Mathematics, 2019 The 2-closure G(2) of a permutation group G on a finite set Ω is the largest subgroup of Sym(Ω) which has the same orbits as G in the induced action on Ω × Ω.
Yu Xue, Pan Jiangmin
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A characterization of cayley graphs of Brandt semigroups
, 2012 In this paper, first we characterize Cayley graphs of finite Brandt semigroups, and we give a criterion to check whether a finite digraph is a Cayley graph of a finite Brandt semigroup.
Wan Saripah Wan Sulaiman
core
Finite groups with star-free noncyclic graphs
Open Mathematics, 2019 For a finite noncyclic group G, let Cyc(G) be the set of elements a of G such that 〈a, b〉 is cyclic for each b of G. The noncyclic graph of G is a graph with the vertex set G ∖ Cyc(G), having an edge between two distinct vertices x and y if 〈x, y〉 is not
Ma Xuanlong, Walls Gary L., Wang Kaishun
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End-regular and End-orthodox generalized lexicographic products of bipartite graphs
Open Mathematics, 2016 A graph X is said to be End-regular (End-orthodox) if its endomorphism monoid End(X) is a regular (orthodox) semigroup. In this paper, we determine the End-regular and the End-orthodox generalized lexicographic products of bipartite graphs.
Gu Rui, Hou Hailong
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The edge-regular complete maps
Open Mathematics, 2020 A map is called edge-regular if it is edge-transitive but not arc-transitive. In this paper, we show that a complete graph Kn{K}_{n} has an orientable edge-regular embedding if and only if n=pd>3n={p}^{d}\gt 3 with p an odd prime such that pd≡3{p}^{d ...
Yu Xue, Lou Ben Gong
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