8 research outputs found

    Locating and Total Dominating Sets of Direct Products of Complete Graphs

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    A set S of vertices in a graph G = (V,E) is a metric-locating-total dominating set of G if every vertex of V is adjacent to a vertex in S and for every u ≠ v in V there is a vertex x in S such that d(u,x) ≠ d(v,x). The metric-location-total domination number \gamma^M_t(G) of G is the minimum cardinality of a metric-locating-total dominating set in G. For graphs G and H, the direct product G × H is the graph with vertex set V(G) × V(H) where two vertices (x,y) and (v,w) are adjacent if and only if xv in E(G) and yw in E(H). In this paper, we determine the lower bound of the metric-location-total domination number of the direct products of complete graphs. We also determine some exact values for some direct products of two complete graphs

    On the diameter of the Kronecker product graph

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    Let G1G_1 and G2G_2 be two undirected nontrivial graphs. The Kronecker product of G1G_1 and G2G_2 denoted by G1⊗G2G_1\otimes G_2 with vertex set V(G1)×V(G2)V(G_1)\times V(G_2), two vertices x1x2x_1x_2 and y1y2y_1y_2 are adjacent if and only if (x1,y1)∈E(G1)(x_1,y_1)\in E(G_1) and (x2,y2)∈E(G2)(x_2,y_2)\in E(G_2). This paper presents a formula for computing the diameter of G1⊗G2G_1\otimes G_2 by means of the diameters and primitive exponents of factor graphs.Comment: 9 pages, 18 reference

    Dominating direct products of graphs

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    AbstractAn upper bound for the domination number of the direct product of graphs is proved. It in particular implies that for any graphs G and H, γ(G×H)⩽3γ(G)γ(H). Graphs with arbitrarily large domination numbers are constructed for which this bound is attained. Concerning the upper domination number we prove that Γ(G×H)⩾Γ(G)Γ(H), thus confirming a conjecture from [R. Nowakowski, D.F. Rall, Associative graph products and their independence, domination and coloring numbers, Discuss. Math. Graph Theory 16 (1996) 53–79]. Finally, for paired-domination of direct products we prove that γpr(G×H)⩽γpr(G)γpr(H) for arbitrary graphs G and H, and also present some infinite families of graphs that attain this bound

    BILANGAN INVERS DOMINASI TOTAL GRAF HELM TERTUTUP, GRAF GEAR, GRAF RODA GANDA DAN GRAF ANTIWEB-GEAR

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    Artikel ini membahas tentang bilangan invers dominasi total pada suatu graf  yang merupakan graf sederhana, berhingga, tak berarah dan tidak memuat simpul terasing, dengan  adalah himpunan titik dan  adalah himpunan sisi. Himpunan  adalah himpunan dominasi di  jika setiap elemen di  bertetangga sedikitnya dengan satu simpul di . Jika , maka  disebut himpunan dominasi total. Himpunan dominasi dan dominasi total tidak tunggal. Dimisalkan  merupakan himpunan dominasi total dengan kardinalitas terkecil. Jika  memuat himpunan dominasi total  maka  disebut himpunan invers dominasi total. Kardinalitas terkecil dari himpunan invers dominasi total disebut bilangan invers dominasi total yang dilambangkan . Suatu graf yang mempunyai himpunan dominasi total belum tentu memiliki himpunan invers dominasi total. Untuk kasus tersebut, bilangan invers dominasi total juga tidak dapat ditentukan. Pada artikel ini, ditentukan bilangan invers dominasi total dari beberapa kelas graf yaitu graf helm tertutup, graf gear, graf roda ganda dan graf antiweb-gear

    Domination in graphs with application to network reliability

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    In this thesis we investigate different domination-related graph polynomials, like the connected domination polynomial, the independent domination polynomial, and the total domination polynomial. We prove some basic properties of these polynomials and obtain formulas for the calculation in special graph classes. Furthermore, we also prove results about the calculation of the different graph polynomials in product graphs and different representations of the graph polynomials. One focus of this thesis lays on the generalization of domination-related polynomials. In this context the trivariate domination polynomial is defined and some results about the bipartition polynomial, which is also a generalization of the domination polynomial, is presented. These two polynomials have many useful properties and interesting connections to other graph polynomials. Furthermore, some more general domination-related polynomials are defined in this thesis, which shows some possible directions for further research.In dieser Dissertation werden verschiedene, zum Dominationspolynom verwandte, Graphenpolynome, wie das zusammenhängende Dominationspolynom, das unabhängige Dominationspolynom und das totale Dominationspolynom, untersucht. Es werden grundlegende Eigenschaften erforscht und Sätze für die Berechnung dieser Polynome in speziellen Graphenklassen bewiesen. Weiterhin werden Ergebnisse für die Berechnung in Produktgraphen und verschiedene Repräsentationen für diese Graphenpolynome gezeigt. Ein Fokus der Dissertation liegt auf der Verallgemeinerung der verschiedenen Dominationspolynome. In diesem Zusammenhang wird das trivariate Dominationspolynom definiert. Außerdem werden Ergebnisse für das Bipartitionspolynom bewiesen. Diese beiden Polynome haben viele interessante Eigenschaften und Beziehungen zu anderen Graphenpolynomen. Darüber hinaus werden weitere multivariate Graphenpolynome definiert, die eine mögliche Richtung für weitere Forschung auf diesem Gebiet aufzeigen
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