reserve R for commutative Ring;
reserve A for non degenerated commutative Ring;
reserve I,J,q for Ideal of A;
reserve p for prime Ideal of A;
reserve M,M1,M2 for Ideal of A/q;

theorem Th28:
    (canHom q)"([#](A/q)) = [#]A
    proof
      (canHom q)"([#](A/q)) = (canHom q)"(rng(canHom q))by FUNCT_2:def 3
      .= dom(canHom q) by RELAT_1:134 .= [#]A by FUNCT_2:def 1;
      hence thesis;
    end;
