X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fmatita%2Flibrary%2Fnat%2Ffactorization.ma;h=8c50d1d7db1e5612e160776b39a59e55ab21fece;hb=10f29fdd78ee089a9a94446207b543d33d6c851c;hp=37a7045924540be5f718043bc79eba2c3c742842;hpb=6423f1b6e3056883016598e454c55cab1004dfd2;p=helm.git

diff --git a/helm/software/matita/library/nat/factorization.ma b/helm/software/matita/library/nat/factorization.ma
index 37a704592..8c50d1d7d 100644
--- a/helm/software/matita/library/nat/factorization.ma
+++ b/helm/software/matita/library/nat/factorization.ma
@@ -15,14 +15,32 @@
 set "baseuri" "cic:/matita/nat/factorization".
 
 include "nat/ord.ma".
-include "nat/gcd.ma".
-include "nat/nth_prime.ma".
 
 (* the following factorization algorithm looks for the largest prime
    factor. *)
 definition max_prime_factor \def \lambda n:nat.
 (max n (\lambda p:nat.eqb (n \mod (nth_prime p)) O)).
 
+theorem lt_SO_max_prime: \forall m. S O <  m \to 
+S O < max m (λi:nat.primeb i∧divides_b i m).
+intros.
+apply (lt_to_le_to_lt ? (smallest_factor m))
+  [apply lt_SO_smallest_factor.assumption
+  |apply f_m_to_le_max
+    [apply le_smallest_factor_n
+    |apply true_to_true_to_andb_true
+      [apply prime_to_primeb_true.
+       apply prime_smallest_factor_n.
+       assumption
+      |apply divides_to_divides_b_true
+        [apply lt_O_smallest_factor.apply lt_to_le.assumption
+        |apply divides_smallest_factor_n.
+         apply lt_to_le.assumption
+        ]
+      ]
+    ]
+  ]
+qed.
 (* max_prime_factor is indeed a factor *)
 theorem divides_max_prime_factor_n:
   \forall n:nat. (S O) < n
@@ -40,19 +58,18 @@ cut (\exists i. nth_prime i = smallest_factor n);
       | rewrite > H1;
         apply le_smallest_factor_n; ]
     | rewrite > H1;
-      (*CSC: simplify here does something nasty! *)
       change with (divides_b (smallest_factor n) n = true);
       apply divides_to_divides_b_true;
       [ apply (trans_lt ? (S O));
         [ unfold lt; apply le_n;
         | apply lt_SO_smallest_factor; assumption; ]
-      | letin x \def le.auto new.
+      | letin x \def le.autobatch new.
          (*       
        apply divides_smallest_factor_n;
         apply (trans_lt ? (S O));
         [ unfold lt; apply le_n;
         | assumption; ] *) ] ]
-  | auto. 
+  | autobatch. 
     (* 
     apply prime_to_nth_prime;
     apply prime_smallest_factor_n;
@@ -70,8 +87,8 @@ apply divides_to_divides_b_true.
 cut (prime (nth_prime (max_prime_factor n))).
 apply lt_O_nth_prime_n.apply prime_nth_prime.
 cut (nth_prime (max_prime_factor n) \divides n).
-auto.
-auto.
+autobatch.
+autobatch.
 (*
   [ apply (transitive_divides ? n);
     [ apply divides_max_prime_factor_n.
@@ -101,6 +118,19 @@ elim (le_to_or_lt_eq ? ? H)
   ]
 qed.
 
+theorem max_prime_factor_to_not_p_ord_O : \forall n,p,r.
+  (S O) < n \to
+  p = max_prime_factor n \to
+  p_ord n (nth_prime p) \neq pair nat nat O r.
+intros.unfold Not.intro.
+apply (p_ord_O_to_not_divides ? ? ? ? H2)
+  [apply (trans_lt ? (S O))[apply lt_O_S|assumption]
+  |rewrite > H1.
+   apply divides_max_prime_factor_n.
+   assumption
+  ]
+qed.
+
 theorem p_ord_to_lt_max_prime_factor: \forall n,p,q,r. O < n \to
 p = max_prime_factor n \to 
 (pair nat nat q r) = p_ord n (nth_prime p) \to
@@ -116,7 +146,7 @@ apply divides_max_prime_factor_n.
 assumption.unfold Not.
 intro.
 cut (r \mod (nth_prime (max_prime_factor n)) \neq O);
-  [unfold Not in Hcut1.auto new.
+  [unfold Not in Hcut1.autobatch new.
     (*
     apply Hcut1.apply divides_to_mod_O;
     [ apply lt_O_nth_prime_n.
@@ -125,7 +155,7 @@ cut (r \mod (nth_prime (max_prime_factor n)) \neq O);
     *)
   |letin z \def le.
    cut(pair nat nat q r=p_ord_aux n n (nth_prime (max_prime_factor n)));
-   [2: rewrite < H1.assumption.|letin x \def le.auto width = 4 new]
+   [2: rewrite < H1.assumption.|letin x \def le.autobatch width = 4 depth = 2]
    (* CERCA COME MAI le_n non lo applica se lo trova come Const e non Rel *)
   ].
 (*
@@ -164,6 +194,33 @@ assumption.apply sym_eq.assumption.assumption.assumption.
 apply (le_to_or_lt_eq ? p H1).
 qed.
 
+lemma lt_max_prime_factor_to_not_divides: \forall n,p:nat.
+O < n \to n=S O \lor max_prime_factor n < p \to 
+(nth_prime p \ndivides n).
+intros.unfold Not.intro.
+elim H1
+  [rewrite > H3 in H2.
+   apply (le_to_not_lt (nth_prime p) (S O))
+    [apply divides_to_le[apply le_n|assumption]
+    |apply lt_SO_nth_prime_n
+    ]
+  |apply (not_le_Sn_n p).
+   change with (p < p).
+   apply (le_to_lt_to_lt ? ? ? ? H3).
+   unfold max_prime_factor.
+   apply  f_m_to_le_max
+    [apply (trans_le ? (nth_prime p))
+      [apply lt_to_le.
+       apply lt_n_nth_prime_n
+      |apply divides_to_le;assumption
+      ]
+    |apply eq_to_eqb_true.
+     apply divides_to_mod_O
+      [apply lt_O_nth_prime_n|assumption]
+    ]
+  ]
+qed.
+
 (* datatypes and functions *)
 
 inductive nat_fact : Set \def
@@ -316,7 +373,7 @@ theorem defactorize_factorize: \forall n:nat.defactorize (factorize n) = n.
 intro.
 apply (nat_case n).reflexivity.
 intro.apply (nat_case m).reflexivity.
-intro.(*CSC: simplify here does something really nasty *)
+intro.
 change with  
 (let p \def (max (S(S m1)) (\lambda p:nat.eqb ((S(S m1)) \mod (nth_prime p)) O)) in
 defactorize (match p_ord (S(S m1)) (nth_prime p) with
@@ -337,7 +394,6 @@ simplify.
 cut ((S(S m1)) = (nth_prime p) \sup q *r).
 cut (O<r).
 rewrite > defactorize_aux_factorize_aux.
-(*CSC: simplify here does something really nasty *)
 change with (r*(nth_prime p) \sup (S (pred q)) = (S(S m1))).
 cut ((S (pred q)) = q).
 rewrite > Hcut2.
@@ -355,7 +411,6 @@ apply (divides_max_prime_factor_n (S (S m1))).
 unfold lt.apply le_S_S.apply le_S_S. apply le_O_n.
 cut ((S(S m1)) = r).
 rewrite > Hcut3 in \vdash (? (? ? %)).
-(*CSC: simplify here does something really nasty *)
 change with (nth_prime p \divides r \to False).
 intro.
 apply (p_ord_aux_to_not_mod_O (S(S m1)) (S(S m1)) (nth_prime p) q r).
@@ -399,7 +454,6 @@ apply (not_eq_O_S (S m1)).
 rewrite > Hcut.rewrite < H1.rewrite < times_n_O.reflexivity.
 apply le_to_or_lt_eq.apply le_O_n.
 (* prova del cut *)
-goal 20.
 apply (p_ord_aux_to_exp (S(S m1))).
 apply lt_O_nth_prime_n.
 assumption.
@@ -433,28 +487,86 @@ apply (witness ? ? (n2* (nth_prime i) \sup n)).
 reflexivity.
 qed.
 
-theorem divides_exp_to_divides: 
-\forall p,n,m:nat. prime p \to 
-p \divides n \sup m \to p \divides n.
-intros 3.elim m.simplify in H1.
-apply (transitive_divides p (S O)).assumption.
-apply divides_SO_n.
-cut (p \divides n \lor p \divides n \sup n1).
-elim Hcut.assumption.
-apply H.assumption.assumption.
-apply divides_times_to_divides.assumption.
-exact H2.
-qed.
-
-theorem divides_exp_to_eq: 
-\forall p,q,m:nat. prime p \to prime q \to
-p \divides q \sup m \to p = q.
+lemma eq_p_max: \forall n,p,r:nat. O < n \to
+O < r \to
+r = (S O) \lor (max r (\lambda p:nat.eqb (r \mod (nth_prime p)) O)) < p \to
+p = max_prime_factor (r*(nth_prime p)\sup n).
 intros.
-unfold prime in H1.
-elim H1.apply H4.
-apply (divides_exp_to_divides p q m).
-assumption.assumption.
-unfold prime in H.elim H.assumption.
+apply sym_eq.
+unfold max_prime_factor.
+apply max_spec_to_max.
+split
+  [split
+    [rewrite > times_n_SO in \vdash (? % ?).
+     rewrite > sym_times.
+     apply le_times
+      [assumption
+      |apply lt_to_le.
+       apply (lt_to_le_to_lt ? (nth_prime p))
+        [apply lt_n_nth_prime_n
+        |rewrite > exp_n_SO in \vdash (? % ?).
+         apply le_exp
+          [apply lt_O_nth_prime_n
+          |assumption
+          ]
+        ]
+      ]
+    |apply eq_to_eqb_true.
+     apply divides_to_mod_O
+      [apply lt_O_nth_prime_n
+      |apply (lt_O_n_elim ? H).
+       intro.
+       apply (witness ? ? (r*(nth_prime p \sup m))).
+       rewrite < assoc_times.
+       rewrite < sym_times in \vdash (? ? ? (? % ?)).
+       rewrite > exp_n_SO in \vdash (? ? ? (? (? ? %) ?)).
+       rewrite > assoc_times.
+       rewrite < exp_plus_times.
+       reflexivity
+      ]
+    ]
+  |intros.  
+   apply not_eq_to_eqb_false.
+   unfold Not.intro.
+   lapply (mod_O_to_divides ? ? ? H5)
+    [apply lt_O_nth_prime_n
+    |cut (Not (divides (nth_prime i) ((nth_prime p)\sup n)))
+      [elim H2
+        [rewrite > H6 in Hletin.
+         simplify in Hletin.
+         rewrite < plus_n_O in Hletin.
+         apply Hcut.assumption
+        |elim (divides_times_to_divides ? ? ? ? Hletin)
+          [apply (lt_to_not_le ? ? H3).
+           apply lt_to_le. 
+           apply (le_to_lt_to_lt ? ? ? ? H6).
+           apply f_m_to_le_max
+            [apply (trans_le ? (nth_prime i))
+              [apply lt_to_le.
+               apply lt_n_nth_prime_n
+              |apply divides_to_le[assumption|assumption]
+              ]
+            |apply eq_to_eqb_true.
+             apply divides_to_mod_O
+              [apply lt_O_nth_prime_n|assumption]
+            ]
+          |apply prime_nth_prime
+          |apply Hcut.assumption
+          ]
+        ]
+      |unfold Not.intro.
+       apply (lt_to_not_eq ? ? H3).
+       apply sym_eq.
+       elim (prime_nth_prime p).
+       apply injective_nth_prime.
+       apply H8
+        [apply (divides_exp_to_divides ? ? ? ? H6).
+         apply prime_nth_prime.
+        |apply lt_SO_nth_prime_n
+        ]
+      ]
+    ]
+  ]
 qed.
 
 theorem  not_divides_defactorize_aux: \forall f:nat_fact. \forall i,j:nat.
@@ -641,7 +753,7 @@ exact H1.
 qed.
 
 theorem factorize_defactorize: 
-\forall f,g: nat_fact_all. factorize (defactorize f) = f.
+\forall f: nat_fact_all. factorize (defactorize f) = f.
 intros.
 apply injective_defactorize.
 apply defactorize_factorize.