X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fmatita%2Flibrary%2Fnat%2Ffactorial.ma;fp=helm%2Fmatita%2Flibrary%2Fnat%2Ffactorial.ma;h=22a799d07d33dade987df8242d1d7ba338442e54;hb=fb94e5a71be508516514dfe50528ccfb3cd2da91;hp=d792574e301087faf246efb23e03ac9e2d86b973;hpb=0a0be269948344318ebbab5593b458aa95313df8;p=helm.git diff --git a/helm/matita/library/nat/factorial.ma b/helm/matita/library/nat/factorial.ma index d792574e3..22a799d07 100644 --- a/helm/matita/library/nat/factorial.ma +++ b/helm/matita/library/nat/factorial.ma @@ -25,32 +25,32 @@ interpretation "factorial" 'fact n = (cic:/matita/nat/factorial/fact.con n). theorem le_SO_fact : \forall n. (S O) \le n!. intro.elim n.simplify.apply le_n. -change with (S O) \le (S n1)*n1!. -apply trans_le ? ((S n1)*(S O)).simplify. +change with ((S O) \le (S n1)*n1!). +apply (trans_le ? ((S n1)*(S O))).simplify. apply le_S_S.apply le_O_n. apply le_times_r.assumption. qed. theorem le_SSO_fact : \forall n. (S O) < n \to (S(S O)) \le n!. -intro.apply nat_case n.intro.apply False_ind.apply not_le_Sn_O (S O) H. -intros.change with (S (S O)) \le (S m)*m!. -apply trans_le ? ((S(S O))*(S O)).apply le_n. +intro.apply (nat_case n).intro.apply False_ind.apply (not_le_Sn_O (S O) H). +intros.change with ((S (S O)) \le (S m)*m!). +apply (trans_le ? ((S(S O))*(S O))).apply le_n. apply le_times.exact H.apply le_SO_fact. qed. theorem le_n_fact_n: \forall n. n \le n!. intro. elim n.apply le_O_n. -change with S n1 \le (S n1)*n1!. -apply trans_le ? ((S n1)*(S O)). +change with (S n1 \le (S n1)*n1!). +apply (trans_le ? ((S n1)*(S O))). rewrite < times_n_SO.apply le_n. apply le_times.apply le_n. apply le_SO_fact. qed. theorem lt_n_fact_n: \forall n. (S(S O)) < n \to n < n!. -intro.apply nat_case n.intro.apply False_ind.apply not_le_Sn_O (S(S O)) H. -intros.change with (S m) < (S m)*m!. -apply lt_to_le_to_lt ? ((S m)*(S (S O))). +intro.apply (nat_case n).intro.apply False_ind.apply (not_le_Sn_O (S(S O)) H). +intros.change with ((S m) < (S m)*m!). +apply (lt_to_le_to_lt ? ((S m)*(S (S O)))). rewrite < sym_times. simplify. apply le_S_S.rewrite < plus_n_O.