Journal of Combinatorial Theory Series B ( IF 1.2 ) Pub Date : 2024-01-23 , DOI: 10.1016/j.jctb.2024.01.001 Primož Potočnik , Micael Toledo , Gabriel Verret
In this paper we investigate orders, longest cycles and the number of cycles of automorphisms of finite vertex-transitive graphs. In particular, we show that the order of every automorphism of a connected vertex-transitive graph with n vertices and of valence d, , is at most where and . Whether such a constant exists for valencies larger than 4 remains an unanswered question. Further, we prove that every automorphism g of a finite connected 3-valent vertex-transitive graph Γ, , has a regular orbit, that is, an orbit of of length equal to the order of g. Moreover, we prove that in this case either Γ belongs to a well understood family of exceptional graphs or at least 5/12 of the vertices of Γ belong to a regular orbit of g. Finally, we give an upper bound on the number of orbits of a cyclic group of automorphisms C of a connected 3-valent vertex-transitive graph Γ in terms of the number of vertices of Γ and the length of a longest orbit of C.
中文翻译:
关于顶点传递图的自同构阶
在本文中,我们研究有限顶点传递图自同构的阶数、最长循环和循环数。特别是,我们证明了具有n 个顶点且价为d的连通顶点传递图的每个自同构的阶,, 至多是在哪里和。是否有这样的常数大于 4 的化合价是否存在仍然是一个悬而未决的问题。此外,我们证明有限连通三价顶点传递图 Г 的每个自同构g ,,有一个规则轨道,即轨道长度等于g的量级。此外,我们证明在这种情况下,要么 Г 属于一个很好理解的异常图族,要么 Г 的至少 5/12 的顶点属于g的规则轨道。最后,我们根据 Γ 的顶点数和 C 的最长轨道的长度给出连通的三价顶点传递图 Г 的自同构循环群C的轨道数的上限。