数学季刊 ›› 2023, Vol. 38 ›› Issue (4): 349-359.doi: 10.13371/j.cnki.chin.q.j.m.2023.04.002

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两类四圈图的奇异性

  

  1. 1. School of Mathematics and Statistics, Qinghai Minzu University, Xining 810007, China; 2. School of Mathematics and Statistics, Qinghai Normal University, Xining 810008, China
  • 收稿日期:2022-11-14 出版日期:2023-12-30 发布日期:2023-12-30
  • 通讯作者: MA Hai-cheng (1965-), male, native of Menyuan, Qinghai, professor of Qinghai Minzu University, engages in algebra graph theory; E-mail: qhmymhc@163.com
  • 作者简介: YOU Xiao-jie (1998-), female, native of Taiyuan, Shanxi, graduate student of Qinghai Minzu University, engages in algebra; MA Hai-cheng (1965-), male, native of Menyuan, Qinghai, professor of Qinghai Minzu University, engages in algebra graph theory; Zhang Bin (1992-), male, native of Xining, Qinghai, lecturer of Qinghai Minzu University, engages in computational biology; LI Ya-lan (1986-), female, native of Xining, Qinghai, associate professor of Qinghai Normal University, engages in algebra graph theory.
  • 基金资助:
    Supported by National Natural Science Foundation of China (Grant No.11561056); National Natural Science Foundation of Qinghai Provence (Grant No. 2022-ZJ-924); Innovation Project of Qinghai Minzu University (Grant No.07M2022002).

Singularity of Two Kinds of Four Cycle Graphs

  1. 1. School of Mathematics and Statistics, Qinghai Minzu University, Xining 810007, China; 2. School of Mathematics and Statistics, Qinghai Normal University, Xining 810008, China
  • Received:2022-11-14 Online:2023-12-30 Published:2023-12-30
  • Contact: MA Hai-cheng (1965-), male, native of Menyuan, Qinghai, professor of Qinghai Minzu University, engages in algebra graph theory; E-mail: qhmymhc@163.com
  • About author: YOU Xiao-jie (1998-), female, native of Taiyuan, Shanxi, graduate student of Qinghai Minzu University, engages in algebra; MA Hai-cheng (1965-), male, native of Menyuan, Qinghai, professor of Qinghai Minzu University, engages in algebra graph theory; Zhang Bin (1992-), male, native of Xining, Qinghai, lecturer of Qinghai Minzu University, engages in computational biology; LI Ya-lan (1986-), female, native of Xining, Qinghai, associate professor of Qinghai Normal University, engages in algebra graph theory.
  • Supported by:
    Supported by National Natural Science Foundation of China (Grant No.11561056); National Natural Science Foundation of Qinghai Provence (Grant No. 2022-ZJ-924); Innovation Project of Qinghai Minzu University (Grant No.07M2022002).

摘要:  Let G be a finite simple graph and A(G) be its adjacency matrix. Then G is singular if A(G) is singular. The graph obtained by bonding the starting vertices and ending vertices of three paths Pa1, Pa2 , Pa3 is called θ-graph, represented by θ(a1,a2,a3). The graph obtained by bonding the two end vertices of the path Ps to the vertices of the θ(a1,a2,a3) and θ(b1,b2,b3) of degree three, respectively, is denoted by α(a1,a2,a3,s,b1,b2,b3) and called α-graph. β-graph is denoted when β(a1,a2,a3,b1,b2,b3) =α(a1,a2,a3,1,b1,b2,b3). In this paper, we give the necessary and sufficient conditions for the singularity of α-graph and β-graph, and prove that the probability that a random given α-graph and β-graph is a singular graph is equal to 1423/2048 and 733/1024 , respectively.

关键词: Adjacency matrix, Singular graph, Nullity, Probability

Abstract:  Let G be a finite simple graph and A(G) be its adjacency matrix. Then G is singular if A(G) is singular. The graph obtained by bonding the starting vertices and ending vertices of three paths Pa1, Pa2 , Pa3 is called θ-graph, represented by θ(a1,a2,a3). The graph obtained by bonding the two end vertices of the path Ps to the vertices of the θ(a1,a2,a3) and θ(b1,b2,b3) of degree three, respectively, is denoted by α(a1,a2,a3,s,b1,b2,b3) and called α-graph. β-graph is denoted when β(a1,a2,a3,b1,b2,b3) =α(a1,a2,a3,1,b1,b2,b3). In this paper, we give the necessary and sufficient conditions for the singularity of α-graph and β-graph, and prove that the probability that a random given α-graph and β-graph is a singular graph is equal to 1423/2048 and 733/1024 , respectively.

Key words: Adjacency matrix, Singular graph, Nullity, Probability

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