reserve M,N for AbGroup;

theorem Th6:
  for M be AbGroup for f,g be Endomorphism of M holds
    f in Funcs(the carrier of M,the carrier of M) &
    g in Funcs(the carrier of M,the carrier of M) &
    (mult_End(M)).[f,g] = (FuncComp(M)).(f,g) &
    (FuncComp(M)).(f,g) is Endomorphism of M
    proof
      let M be AbGroup;
      let f,g be Endomorphism of M;
      f in set_End(M) & g in set_End(M);
      hence thesis by Th5,ZFMISC_1:87,FUNCT_1:49;
    end;
