theorem Th5:
  |- f^<*p*> implies |- f^g^<*p*>
proof
A1: Ant(f^<*p*>) = f & Ant(f^g^<*p*>) = f^g by CALCUL_1:5;
  Suc(f^g^<*p*>) = p by CALCUL_1:5;
  then
A2: Suc(f^<*p*>) = Suc(f^g^<*p*>) by CALCUL_1:5;
  assume |- f^<*p*>;
  hence thesis by A1,A2,CALCUL_1:8,36;
end;
