arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1305.5145math.CO
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镜像二部图

Mirror bipartite graphs

Susana-Clara López, Francesc-Antoni Muntaner-Batle

摘要:

直观地说,一个二部图是镜像的,如果它可以在笛卡尔平面上以这样的方式绘制,即一个稳定集的顶点是x=0中的点,另一个稳定集的顶点是x=1中的点,边是连接邻顶点的直线段,并且所得到的配置关于线x=1/2对称。镜像二部图的概念在研究某些类型的图的乘积时自然出现,例如Kronecker乘积。基于这一事实,我们从镜像二部图的度序列和度集的角度研究了镜像二部图。刻画了镜像二部图的度序列。我们还证明了从一个给定的正整数集合P,我们可以构造一个阶为2 max P的二部图,它是镜像的.此外,很少知道的度序列的图与回路连接,当连接的回路的数量是有限的。本文证明了镜像二部图是研究这类图的度序列的一个有力工具,当图的每个顶点所连接的圈数至多为$1$时,镜像二部图是研究这类图的度序列的一个有力工具.

英文摘要:

Intuitively speaking, a bipartite graph is mirror if it can be drawn in the Cartesian plane in such a way that, the vertices of one stable are points in x=0, the vertices of the other stable set are points in x=1, the edges are straight line segments joining adjacent vertices and the resulting configuration is symmetric with respect to the line x=1/2. The concept of mirror bipartite graph appears naturally when studying certain types of products of graphs as for instance the Kronecker product. Motivated by this fact, we study mirror bipartite graphs from the point of view of their degree sequences and of their degree sets. We characterize the sequences of degrees of mirror bipartite graphs. We also show that from a given set P of positive integers, we can construct a bipartite graph of order 2max P, which is mirror. Furthermore, very little is known for the degree sequences of graphs with loops attached, when the number of loops attached is limited. We show in this paper that mirror bipartite graphs constitute a powerful tool to study the degree sequences of these graphs when the number of loops attached at each vertex is at most $1$.

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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