SetDirectory[NotebookDirectory[]];(*设置工作路径为当前笔记本路径*)
Needs["GroupTheory`"](*安装工具包*)

c4v=GTInstallGroup[C4v,GOVerbose->False];
c4=GTInstallGroup[C4,GOVerbose->False]
GTQuotientGroupQ[c4v,c4](*判断c4与c4v构成商群*)
GTQuotientGroup[c4v,c4](*求解这这两个群所构成的商群*)