【摘要】 利用不等式估值和对ｎ的归纳法给出了Ａｎ（ｎ≥５）单性的又一证明．更多还原

【Abstract】 In this note we give another proof to the simplicity of alternating groups An(n ≥ 5) , The method of ours is by induction and an estimate for the length of conjugacy classes of elements in An is used to prove that An has no regular normal subgroups.更多还原