1999年,Frisch描述了Z/p^2Z上多项式置换群的结构.2005年,张找到Z/p^2Z上多项式函数与Z/pZ上多项式函数的3维向量之间的对应关系.本文首先证明在任意有限交换环R上,多项式置换群同构于R[x](作为R上多项式函数全体构成的R-代数)的自同构群,然后用张所提出的对应对Frisch的描述给出一个新证明.
Frisch characterized the structure of the group of polynomial permutations over Z/p^2Z in 1999.Zhang found a correspondence between polynomial functions over Z/p^2Z and 3-tuples of polynomial functions over Z/pZ in 2005.In this paper,we first prove that over any finite commutative ring R,the group of polynomial permutations is isomorphic to the automorphism group of the R-algebra of the polynomial functions.Then we give an easy proof to the characterization of Frisch using the correspondence set proposed by Zhang.