(* *)
(**************************************************************************)
-set "baseuri" "cic:/matita/demodulation_matita/".
+
include "nat/minus.ma".
theorem p2: \forall x,y:nat. x+x = (S(S O))*x.
-intros.demodulate.reflexivity.
+intros.
+demodulate by times_n_Sm times_n_O sym_times plus_n_O.
qed.
theorem p4: \forall x:nat. (x+(S O))*(x-(S O))=x*x - (S O).