Journal of Combinatorial Theory Series B ( IF 1.2 ) Pub Date : 2020-12-16 , DOI: 10.1016/j.jctb.2020.12.001 Binzhou Xia
Half-arc-transitive graphs are a fascinating topic which connects graph theory, Riemann surfaces and group theory. Although fruitful results have been obtained over the last half a century, it is still challenging to construct half-arc-transitive graphs with prescribed vertex stabilizers. Until recently, there have been only six known connected tetravalent half-arc-transitive graphs with nonabelian vertex stabilizers, and the question whether there exists a connected tetravalent half-arc-transitive graph with nonabelian vertex stabilizer of order for every has been wide open. This question is answered in the affirmative in this paper via the construction of a connected tetravalent half-arc-transitive graph with vertex stabilizer for each integer , where is the direct product of two copies of the dihedral group of order 8 and is the direct product of m copies of the cyclic group of order 2. The graphs constructed have surprisingly many significant properties in various contexts.
中文翻译:
具有无界nonabelian顶点稳定器的四价半弧传递图
半弧传递图是连接图论,黎曼曲面和群论的一个引人入胜的话题。尽管在过去的半个世纪中取得了丰硕的成果,但使用规定的顶点稳定器构造半弧传递图仍然具有挑战性。直到最近,只有六个已知的带有非阿贝尔顶点稳定剂的连接的四价半弧-传递图,以及是否存在一个带非阿贝尔顶点稳定剂的连接的四价半弧-传递图的问题 每一个 已经敞开了。通过建立带有顶点稳定器的连接的四价半弧-传递图的连接,该问题得到了肯定的回答。 对于每个整数 ,在哪里 是8阶二面体组的两个副本的直接乘积, 是2阶环状基团的m个副本的直接乘积。在各种情况下,构造的图都具有令人惊讶的许多重要特性。