Prima versione di bertrand. Tanti cambiamenti qua e la.

[helm.git] / helm / software / matita / library / nat / binomial.ma

diff --git a/helm/software/matita/library/nat/binomial.ma b/helm/software/matita/library/nat/binomial.ma
index 1a341032032b95c317863801601446727cbd983a..e7d58039a34baa3338a98f4c37c8ca459da2a49f 100644 (file)
--- a/helm/software/matita/library/nat/binomial.ma
+++ b/helm/software/matita/library/nat/binomial.ma
@@ -248,4 +248,15 @@ apply eq_sigma_p;intros
    rewrite < times_n_SO.
    reflexivity
   ]
-qed.
\ No newline at end of file
+qed.
+
+theorem exp_Sn_SSO: \forall n. exp (S n) 2 = S((exp n 2) + 2*n).
+intros.simplify.
+rewrite < times_n_SO.
+rewrite < plus_n_O.
+rewrite < sym_times.simplify.
+rewrite < assoc_plus.
+rewrite < sym_plus.
+reflexivity.
+qed.
+