theorem Th61:
  for D being set holds
    the carrier of D*+^+<0> = D* &
    the multF of D*+^+<0> = D-concatenation &
    1.(D*+^+<0>) = {}
proof
  let D be set;
  set M = D*+^+<0>;
  the multMagma of M = D*+^ & the_unity_wrt op(M) = un(M) by Def22,Th17;
  hence thesis by Def34,Th60;
end;
