两个集合，两个函数 If we are to develop efficient error-detecting and error-correcting codes,we will need more sophisticated mathematical tools.Group theory will allow faster methods of encoding and decoding messages.A code is an (n,m)- block code if the information that is to be coded can be divided into blocks of m binary digits,each of which can be encoded into n binary digits.More specifically,an (n,m)-block code consists of an encoding function E:Z→Z and a decoding function D:z5→Z 问题58 其实，这n和m之间大小的差别就是“冗余” 关于m,m的大小，你能说点什么？两个集合，两个函数 其实，这n和m之间大小的差别就是“冗余