• 제목/요약/키워드: union of graphs

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PLITHOGENIC VERTEX DOMINATION NUMBER

  • T. BHARATHI;S. LEO;JEBA SHERLIN MOHAN
    • Journal of applied mathematics & informatics
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    • 제42권3호
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    • pp.625-634
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    • 2024
  • The thrust of this paper is to extend the notion of Plithogenic vertex domination to the basic operations in Plithogenic product fuzzy graphs (PPFGs). When the graph is a complete PPFG, Plithogenic vertex domination numbers (PVDNs) of its Plithogenic complement and perfect Plithogenic complement are the same, since the connectivities are the same in both the graphs. Since extra edges are added to the graph in the case of perfect Plithogenic complement, the PVDN of perfect Plithogenic complement is always less than or equal to that of Plithogenic complement, when the graph under consideration is an incomplete PPFG. The maximum and minimum values of the PVDN of the intersection or the union of PPFGs depend upon the attribute values given to P-vertices, the number of attribute values and the connectivities in the corresponding PPFGs. The novelty in this study is the investigation of the variations and the relations between PVDNs in the operations of Plithogenic complement, perfect Plithogenic complement, union and intersection of PPFGs.

SUFFICIENT CONDITION FOR THE EXISTENCE OF THREE DISJOINT THETA GRAPHS

  • Gao, Yunshu;Ma, Ding
    • 대한수학회보
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    • 제52권1호
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    • pp.287-299
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    • 2015
  • A theta graph is the union of three internally disjoint paths that have the same two distinct end vertices. We show that every graph of order $n{\geq}12$ and size at least ${\lfloor}\frac{11n-18}{2}{\rfloor}$ contains three disjoint theta graphs. As a corollary, every graph of order $n{\geq}12$ and size at least ${\lfloor}\frac{11n-18}{2}{\rfloor}$ contains three disjoint cycles of even length.

SUPER VERTEX MEAN GRAPHS OF ORDER ≤ 7

  • LOURDUSAMY, A.;GEORGE, SHERRY
    • Journal of applied mathematics & informatics
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    • 제35권5_6호
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    • pp.565-586
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    • 2017
  • In this paper we continue to investigate the Super Vertex Mean behaviour of all graphs up to order 5 and all regular graphs up to order 7. Let G(V,E) be a graph with p vertices and q edges. Let f be an injection from E to the set {1,2,3,${\cdots}$,p+q} that induces for each vertex v the label defined by the rule $f^v(v)=Round\;\left({\frac{{\Sigma}_{e{\in}E_v}\;f(e)}{d(v)}}\right)$, where $E_v$ denotes the set of edges in G that are incident at the vertex v, such that the set of all edge labels and the induced vertex labels is {1,2,3,${\cdots}$,p+q}. Such an injective function f is called a super vertex mean labeling of a graph G and G is called a Super Vertex Mean Graph.

ON INTEGRAL GRAPHS WHICH BELONG TO THE CLASS $\bar{{\alpha}K_{a,a}\cup{\beta}K_{b,b}}$

  • LEPOVIC MIRKO
    • Journal of applied mathematics & informatics
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    • 제20권1_2호
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    • pp.61-74
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    • 2006
  • Let G be a simple graph and let G denote its complement. We say that $\bar{G}$ is integral if its spectrum consists of integral values. In this work we establish a characterization of integral graphs which belong to the class $\bar{{\alpha}K_{a,a}\cup{\beta}K_{b,b}}$, where mG denotes the m-fold union of the graph G.

PAIR MEAN CORDIAL LABELING OF SOME UNION OF GRAPHS

  • R. PONRAJ;S. PRABHU
    • Journal of Applied and Pure Mathematics
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    • 제6권1_2호
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    • pp.55-69
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    • 2024
  • Let a graph G = (V, E) be a (p, q) graph. Define $${\rho}=\{\array{{\frac{p}{2}} && p\;\text{is even} \\ {\frac{p-1}{2}} && p\;\text{is odd,}}$$ and M = {±1, ±2, … ± 𝜌} called the set of labels. Consider a mapping λ : V → M by assigning different labels in M to the different elements of V when p is even and different labels in M to p - 1 elements of V and repeating a label for the remaining one vertex when p is odd. The labeling as defined above is said to be a pair mean cordial labeling if for each edge uv of G, there exists a labeling $\frac{{\lambda}(u)+{\lambda}(v)}{2}$ if λ(u) + λ(v) is even and $\frac{{\lambda}(u)+{\lambda}(v)+1}{2}$ if λ(u) + λ(v) is odd such that ${\mid}\bar{\mathbb{s}}_{{\lambda}_1}-\bar{\mathbb{s}}_{{\lambda}^c_1}{\mid}\,{\leq}\,1$ where $\bar{\mathbb{s}}_{{\lambda}_1}$ and $\bar{\mathbb{s}}_{{\lambda}^c_1}$ respectively denote the number of edges labeled with 1 and the number of edges not labeled with 1. A graph G with a pair mean cordial labeling is called a pair mean cordial graph. In this paper, we investigate the pair mean cordial labeling behavior of some union of graphs.

동적 그래프에서 GPU 기반의 점진적 연결 요소 처리 (GPU Based Incremental Connected Component Processing in Dynamic Graphs)

  • 김남영;최도진;복경수;유재수
    • 한국콘텐츠학회논문지
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    • 제22권6호
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    • pp.56-68
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    • 2022
  • 최근 실시간 처리의 요구가 증가하면서 시간에 따라서 변화하는 동적 그래프에 관한 연구가 활발하게 진행되고 있다. 동적 그래프를 분석하기 위한 알고리즘의 하나로 연결 요소가 있다. GPU는 높은 메모리 대역폭, 연산 성능으로 대규모의 그래프 계산에 적합하다. 그러나 동적 그래프의 연결 요소를 GPU를 이용하여 처리할 때, GPU의 제한된 메모리로 인해 실제 그래프 처리 시 CPU와 GPU 간에 잦은 데이터 교환이 발생한다. 본 논문에서는 동적 그래프에서 GPU 기반의 효율적인 점진적 연결 요소 처리 기법을 제안한다. 제안하는 기법은 Weighted-Quick-Union 알고리즘을 기반으로 연결 요소 레이블에 구성 요소의 개수를 이용하여 연결 요소를 빠르게 계산한다. 또한, 재계산할 부분을 판별하여 GPU로 전송할 데이터를 최소화하여 대규모 그래프에 대하여 CPU와 GPU 간의 데이터 교환 횟수를 감소시킨다. 뿐만 아니라 GPU와 CPU 간에 데이터 전송 시간 낭비를 줄이기 위해 GPU와 CPU가 비동기로 실행하는 처리 구조를 제안한다. 실제 데이터 집합을 사용한 성능 평가를 통해 제안하는 기법의 우수성을 입증한다.

최소신장트리를 위한 크루스칼 알고리즘의 효율적인 구현 (An Efficient Implementation of Kruskal's Algorithm for A Minimum Spanning Tree)

  • 이주영
    • 한국컴퓨터정보학회논문지
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    • 제19권7호
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    • pp.131-140
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    • 2014
  • 본 논문에서는 최소신장트리를 구하는 크루스칼 알고리즘의 효율적인 구현 방법을 제시한다. 제시하는 방법은 union-find 자료구조를 이용하며, 노드 집합을 나타내는 각 트리의 깊이를 줄이기 위해 union 연산시 루트까지의 경로에 있는 노드들의 위치를 최종 루트의 자식노드로 직접 이동하여 깊이를 줄이도록 하는 방법이다. 이 방법은 루트까지의 경로를 축소하고 노드의 레벨을 축소시킴으로써 트리의 깊이도 줄일 수 있다. 트리의 깊이가 줄어든다면 노드가 속하는 트리의 루트를 찾는 시간을 줄일 수 있게 되어 효율적인 방법이라 할 수 있다. 본 장에서 제안하는 방법을 그래프로 평가해보고 분석해 본 결과, 기존의 union() 방법이나 경로축소방법인 union2() 보다 트리의 깊이를 작게 유지함을 알 수 있다.

A GENERALIZED IDEAL BASED-ZERO DIVISOR GRAPHS OF NEAR-RINGS

  • Dheena, Patchirajulu;Elavarasan, Balasubramanian
    • 대한수학회논문집
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    • 제24권2호
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    • pp.161-169
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    • 2009
  • In this paper, we introduce the generalized ideal-based zero-divisor graph structure of near-ring N, denoted by $\widehat{{\Gamma}_I(N)}$. It is shown that if I is a completely reflexive ideal of N, then every two vertices in $\widehat{{\Gamma}_I(N)}$ are connected by a path of length at most 3, and if $\widehat{{\Gamma}_I(N)}$ contains a cycle, then the core K of $\widehat{{\Gamma}_I(N)}$ is a union of triangles and rectangles. We have shown that if $\widehat{{\Gamma}_I(N)}$ is a bipartite graph for a completely semiprime ideal I of N, then N has two prime ideals whose intersection is I.

THE AUTOMORPHISM GROUP OF COMMUTING GRAPH OF A FINITE GROUP

  • Mirzargar, Mahsa;Pach, Peter P.;Ashrafi, A.R.
    • 대한수학회보
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    • 제51권4호
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    • pp.1145-1153
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    • 2014
  • Let G be a finite group and X be a union of conjugacy classes of G. Define C(G,X) to be the graph with vertex set X and $x,y{\in}X$ ($x{\neq}y$) joined by an edge whenever they commute. In the case that X = G, this graph is named commuting graph of G, denoted by ${\Delta}(G)$. The aim of this paper is to study the automorphism group of the commuting graph. It is proved that Aut(${\Delta}(G)$) is abelian if and only if ${\mid}G{\mid}{\leq}2$; ${\mid}Aut({\Delta}(G)){\mid}$ is of prime power if and only if ${\mid}G{\mid}{\leq}2$, and ${\mid}Aut({\Delta}(G)){\mid}$ is square-free if and only if ${\mid}G{\mid}{\leq}3$. Some new graphs that are useful in studying the automorphism group of ${\Delta}(G)$ are presented and their main properties are investigated.