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arXiv 1701.07599math.ATmath.AC
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Gallai-单纯复形的拓扑与代数刻画

Topological and Algebraic Characterizations of Gallai-Simplicial Complexes

Imran Ahmed, Shahid Muhmood

摘要:

我们回顾第一个Gallai-单纯复形$Δ_Γ(G)$与平面图$G$的Gallai图$Γ(G)$相关联。欧拉特征线是一种非常有用的拓扑同伦不变量,它可以用来对曲面进行分类。在定理3.2和3.4中,我们分别计算了三角梯图和棱柱图的Gallai单纯复形的Euler特征线。设$G$是$n$顶点上的有限简单图,其形式为$n=3l+2$或$3l+3$。在定理4.4中,我们证明了对于$G$的下列类型的构造,$G$将是$f$-Gallai图。1型。当$n=3l+2$ . $G=\mathbb{S}_{4l}$是由星形图$S_{2l}$和$S'_{2l}$的两个副本组成的图,其中$l\geq 2$具有$l$公共顶点。第二型。当$n=3l+3$。$G=\mathbb{S}_{4l+1}$是由两个星形图$S_{2l}$和$S_{2l+1}$组成的图,其中$l\geq 2$具有$l$公共顶点。

英文摘要:

We recall first Gallai-simplicial complex $Δ_Γ(G)$ associated to Gallai graph $Γ(G)$ of a planar graph $G$. The Euler characteristic is a very useful topological and homotopic invariant to classify surfaces. In Theorems 3.2 and 3.4, we compute Euler characteristics of Gallai-simplicial complexes associated to triangular ladder and prism graphs, respectively. Let $G$ be a finite simple graph on $n$ vertices of the form $n=3l+2$ or $3l+3$. In Theorem 4.4, we prove that $G$ will be $f$-Gallai graph for the following types of constructions of $G$. Type 1. When $n=3l+2$. $G=\mathbb{S}_{4l}$ is a graph consisting of two copies of star graphs $S_{2l}$ and $S'_{2l}$ with $l\geq 2$ having $l$ common vertices. Type 2. When $n=3l+3$. $G=\mathbb{S}_{4l+1}$ is a graph consisting of two star graphs $S_{2l}$ and $S_{2l+1}$ with $l\geq 2$ having $l$ common vertices.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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