20 research outputs found

    On the edge metric dimension and Wiener index of the blow up of graphs

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    Let G=(V,E)G=(V,E) be a connected graph. The distance between an edge e=xye=xy and a vertex vv is defined as \T{d}(e,v)=\T{min}\{\T{d}(x,v),\T{d}(y,v)\}. A nonempty set SV(G)S \subseteq V(G) is an edge metric generator for GG if for any two distinct edges e1,e2E(G)e_1,e_2 \in E(G), there exists a vertex sSs \in S such that \T{d}(e_1,s) \neq \T{d}(e_2,s). An edge metric generating set with the smallest number of elements is called an edge metric basis of GG, and the number of elements in an edge metric basis is called the edge metric dimension of GG and it is denoted by \T{edim}(G). In this paper, we study the edge metric dimension of a blow up of a graph GG, and also we study the edge metric dimension of the zero divisor graph of the ring of integers modulo nn. Moreover, the Wiener index and the hyper-Wiener index of the blow up of certain graphs are computed

    The annihilator ideal graph of a commutative ring

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    Let RR be a commutative ring with nonzero identity and II be a proper ideal of RR. The annihilator graph of RR with respect to II, which is denoted by AGI(R)AG_{I}(R), is the undirected graph with vertex-set V(AGI(R))={xRI:xyI V(AG_{I}(R)) = \lbrace x\in R \setminus I : xy \in I\ for some yI} \ y \notin I \rbrace and two distinct vertices xx and yy are adjacent if and only if AI(xy)AI(x)AI(y)A_{I}(xy)\neq A_{I}(x) \cup A_{I}(y), where AI(x)={rR:rxI}A_{I}(x) = \lbrace r\in R : rx\in I\rbrace. In this paper, we study some basic properties of AGI(R)AG_I(R), and we characterise when AGI(R) AG_{I}(R) is planar, outerplanar or a ring graph. Also, we study the graph AGI(Zn)AG_{I}(\mathbb{Z}_{n}) , where ZnZ_n is the ring of integers modulo nn

    The cozero-divisor graph of a noncommutative ring

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    Some results on the annihilator graph of a commutative ring

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    summary:Let RR be a commutative ring. The annihilator graph of RR, denoted by AG(R){\rm AG}(R), is the undirected graph with all nonzero zero-divisors of RR as vertex set, and two distinct vertices xx and yy are adjacent if and only if annR(xy)annR(x)annR(y){\rm ann}_R(xy) \neq {\rm ann}_R(x)\cup {\rm ann}_R(y), where for zRz \in R, annR(z)={rR ⁣:rz=0}{\rm ann}_R(z) = \lbrace r \in R \colon rz = 0\rbrace . In this paper, we characterize all finite commutative rings RR with planar or outerplanar or ring-graph annihilator graphs. We characterize all finite commutative rings RR whose annihilator graphs have clique number 11, 22 or 33. Also, we investigate some properties of the annihilator graph under the extension of RR to polynomial rings and rings of fractions. For instance, we show that the graphs AG(R){\rm AG}(R) and AG(T(R)){\rm AG}(T(R)) are isomorphic, where T(R)T(R) is the total quotient ring of RR. Moreover, we investigate some properties of the annihilator graph of the ring of integers modulo nn, where n1n \geq 1

    The Planar Index and Outerplanar Index of Some Graphs Associated to Commutative Rings

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    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

    Annihilator graphs of a commutative semigroup whose Zero-divisor graphs are a complete graph with an end vertex

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    Suppose that the zero-divisor graph of a commutative semi-group S, be a complete graph with an end vertex. In this paper, we determine the structure of the annihilator graph S and we show that if Z(S)= S, then the annihilator graph S is a disconnected graph

    On the distinguishing chromatic number of the Kronecker products of graphs

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    AbstractIn this paper, we investigate the distinguishing chromatic number of Kronecker product of paths, cycles, star graphs, symmetric trees, almost symmetric trees, and bisymmetric trees
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