以下几个结论，余味袅袅 Theorem 9.10 The group Zm x Zn is isomorphic to Zmn if and only if gcd(m,n）=1. Corollary 9.11 Let n1,...,nk be positive integers.Then k ΠZn,≥Zn1mk i=1 if and only if gcd(ni,nj)=1 for if j. Corollary 9.12 If m=p…pt, where the pis are distinct primes,then Zm￥Zp71X…XZp以下几个结论，余味袅袅