Extending finite group actions on surfaces over
arXiv:1209.1158
Abstract
Let (resp. and ) and resp. be the maximum order of finite (resp. cyclic and abelian) groups acting on the closed orientable surfaces which extend over among all embeddings and resp. unknotted embeddings . It is known that , and we show that is reached for an unknotted embedding if and only if , 3, 4, 5, 6, 9, 11, 17, 25, 97, 121, 241, 601. Moreover is ; and is for even , and for odd . Efforts are made to see intuitively how these maximal symmetries are embedded into the symmetries of the 3-sphere.
21 pages, 15 figures