From: Andrea Asperti <andrea.asperti@unibo.it>
Date: Mon, 10 Dec 2012 08:56:30 +0000 (+0000)
Subject: Porting chebyshev
X-Git-Tag: make_still_working~1399
X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=commitdiff_plain;h=06873c26e897b423cf2ea4814246fc5c2c5d4346;p=helm.git

Porting chebyshev
---

diff --git a/matita/matita/lib/arithmetics/big_pi.ma b/matita/matita/lib/arithmetics/big_pi.ma
new file mode 100644
index 000000000..94068a088
--- /dev/null
+++ b/matita/matita/lib/arithmetics/big_pi.ma
@@ -0,0 +1,417 @@
+(*
+    ||M||  This file is part of HELM, an Hypertextual, Electronic        
+    ||A||  Library of Mathematics, developed at the Computer Science     
+    ||T||  Department of the University of Bologna, Italy.                     
+    ||I||                                                                 
+    ||T||  
+    ||A||  This file is distributed under the terms of the 
+    \   /  GNU General Public License Version 2        
+     \ /      
+      V_______________________________________________________________ *)
+
+include "arithmetics/primes.ma".
+include "arithmetics/bigops.ma".
+
+theorem sigma_const: ∀n:nat. ∑_{i<n} 1 = n.
+#n elim n // #n1 >bigop_Strue //
+qed.
+
+(* monotonicity; these roperty should be expressed at a more
+genral level *)
+
+theorem le_pi: 
+∀n.∀p:nat → bool.∀g1,g2:nat → nat. 
+  (∀i.i<n → p i = true → g1 i ≤ g2 i ) → 
+  ∏_{i < n | p i} (g1 i) ≤ ∏_{i < n | p i} (g2 i).
+#n #p #g1 #g2 elim n 
+  [#_ @le_n
+  |#n1 #Hind #Hle cases (true_or_false (p n1)) #Hcase
+    [ >bigop_Strue // >bigop_Strue // @le_times
+      [@Hle // |@Hind #i #lti #Hpi @Hle [@lt_to_le @le_S_S @lti|@Hpi]]
+    |>bigop_Sfalse // >bigop_Sfalse // @Hind
+     #i #lti #Hpi @Hle [@lt_to_le @le_S_S @lti|@Hpi]
+    ]
+  ]
+qed.
+    
+theorem exp_sigma: ∀n,a,p. 
+  ∏_{i < n | p i} a = exp a (∑_{i < n | p i} 1).
+#n #a #p elim n // #n1 cases (true_or_false (p n1)) #Hcase
+  [>bigop_Strue // >bigop_Strue // |>bigop_Sfalse // >bigop_Sfalse //] 
+qed.
+
+theorem times_pi: ∀n,p,f,g. 
+  ∏_{i<n|p i}(f i*g i) = ∏_{i<n|p i}(f i) * ∏_{i<n|p i}(g i). 
+#n #p #f #g elim n // #n1 cases (true_or_false (p n1)) #Hcase #Hind
+  [>bigop_Strue // >bigop_Strue // >bigop_Strue //
+  |>bigop_Sfalse // >bigop_Sfalse // >bigop_Sfalse //
+  ]
+qed.
+
+(*
+theorem true_to_pi_p_Sn: ∀n,p,g.
+  p n = true \to pi_p (S n) p g = (g n)*(pi_p n p g).
+intros.
+unfold pi_p.
+apply true_to_iter_p_gen_Sn.
+assumption.
+qed.
+   
+theorem false_to_pi_p_Sn: 
+\forall n:nat. \forall p:nat \to bool. \forall g:nat \to nat.
+p n = false \to pi_p (S n) p g = pi_p n p g.
+intros.
+unfold pi_p.
+apply false_to_iter_p_gen_Sn.
+assumption.
+qed.  
+
+theorem eq_pi_p: \forall p1,p2:nat \to bool.
+\forall g1,g2: nat \to nat.\forall n.
+(\forall x.  x < n \to p1 x = p2 x) \to
+(\forall x.  x < n \to g1 x = g2 x) \to
+pi_p n p1 g1 = pi_p n p2 g2.
+intros.
+unfold pi_p.
+apply eq_iter_p_gen;
+assumption.
+qed.
+
+theorem eq_pi_p1: \forall p1,p2:nat \to bool.
+\forall g1,g2: nat \to nat.\forall n.
+(\forall x.  x < n \to p1 x = p2 x) \to
+(\forall x.  x < n \to p1 x = true \to g1 x = g2 x) \to
+pi_p n p1 g1 = pi_p n p2 g2.
+intros.
+unfold pi_p.
+apply eq_iter_p_gen1;
+assumption.
+qed.
+
+theorem pi_p_false: 
+\forall g: nat \to nat.\forall n.pi_p n (\lambda x.false) g = S O.
+intros.
+unfold pi_p.
+apply iter_p_gen_false.
+qed.
+
+theorem pi_p_times: \forall n,k:nat.\forall p:nat \to bool.
+\forall g: nat \to nat.
+pi_p (k+n) p g 
+= pi_p k (\lambda x.p (x+n)) (\lambda x.g (x+n)) * pi_p n p g.
+intros.
+unfold pi_p.
+apply (iter_p_gen_plusA nat n k p g (S O) times)
+[ apply sym_times.
+| intros.
+  apply sym_eq.
+  apply times_n_SO
+| apply associative_times
+]
+qed.
+
+theorem false_to_eq_pi_p: \forall n,m:nat.n \le m \to
+\forall p:nat \to bool.
+\forall g: nat \to nat. (\forall i:nat. n \le i \to i < m \to
+p i = false) \to pi_p m p g = pi_p n p g.
+intros.
+unfold pi_p.
+apply (false_to_eq_iter_p_gen);
+assumption.
+qed.
+
+theorem or_false_eq_SO_to_eq_pi_p: 
+\forall n,m:nat.\forall p:nat \to bool.
+\forall g: nat \to nat.
+n \le m \to (\forall i:nat. n \le i \to i < m \to p i = false \lor g i = S O)
+\to pi_p m p g = pi_p n p g.
+intros.
+unfold pi_p.
+apply or_false_eq_baseA_to_eq_iter_p_gen
+  [intros.simplify.rewrite < plus_n_O.reflexivity
+  |assumption
+  |assumption
+  ]
+qed.
+
+theorem pi_p2 : 
+\forall n,m:nat.
+\forall p1,p2:nat \to bool.
+\forall g: nat \to nat \to nat.
+pi_p (n*m) 
+  (\lambda x.andb (p1 (div x m)) (p2 (mod x m))) 
+  (\lambda x.g (div x m) (mod x m)) =
+pi_p n p1 
+  (\lambda x.pi_p m p2 (g x)).
+intros.
+unfold pi_p.
+apply (iter_p_gen2 n m p1 p2 nat g (S O) times)
+[ apply sym_times
+| apply associative_times
+| intros.
+  apply sym_eq.
+  apply times_n_SO
+]
+qed.
+
+theorem pi_p2' : 
+\forall n,m:nat.
+\forall p1:nat \to bool.
+\forall p2:nat \to nat \to bool.
+\forall g: nat \to nat \to nat.
+pi_p (n*m) 
+  (\lambda x.andb (p1 (div x m)) (p2 (div x m) (mod x  m))) 
+  (\lambda x.g (div x m) (mod x m)) =
+pi_p n p1 
+  (\lambda x.pi_p m (p2 x) (g x)).
+intros.
+unfold pi_p.
+apply (iter_p_gen2' n m p1 p2 nat g (S O) times)
+[ apply sym_times
+| apply associative_times
+| intros.
+  apply sym_eq.
+  apply times_n_SO
+]
+qed.
+
+lemma pi_p_gi: \forall g: nat \to nat.
+\forall n,i.\forall p:nat \to bool.i < n \to p i = true \to 
+pi_p n p g = g i * pi_p n (\lambda x. andb (p x) (notb (eqb x i))) g.
+intros.
+unfold pi_p.
+apply (iter_p_gen_gi)
+[ apply sym_times
+| apply associative_times
+| intros.
+  apply sym_eq.
+  apply times_n_SO
+| assumption
+| assumption
+]
+qed.
+
+theorem eq_pi_p_gh: 
+\forall g,h,h1: nat \to nat.\forall n,n1.
+\forall p1,p2:nat \to bool.
+(\forall i. i < n \to p1 i = true \to p2 (h i) = true) \to
+(\forall i. i < n \to p1 i = true \to h1 (h i) = i) \to 
+(\forall i. i < n \to p1 i = true \to h i < n1) \to 
+(\forall j. j < n1 \to p2 j = true \to p1 (h1 j) = true) \to
+(\forall j. j < n1 \to p2 j = true \to h (h1 j) = j) \to 
+(\forall j. j < n1 \to p2 j = true \to h1 j < n) \to 
+pi_p n p1 (\lambda x.g(h x)) = pi_p n1 p2 g.
+intros.
+unfold pi_p.
+apply (eq_iter_p_gen_gh nat (S O) times ? ? ? g h h1 n n1 p1 p2)
+[ apply sym_times
+| apply associative_times
+| intros.
+  apply sym_eq.
+  apply times_n_SO
+| assumption
+| assumption
+| assumption
+| assumption
+| assumption
+| assumption
+]
+qed.
+     
+theorem exp_sigma_p: \forall n,a,p. 
+pi_p n p (\lambda x.a) = (exp a (sigma_p n p (\lambda x.S O))).
+intros.
+elim n
+  [reflexivity
+  |apply (bool_elim ? (p n1))
+    [intro.
+     rewrite > true_to_pi_p_Sn
+      [rewrite > true_to_sigma_p_Sn
+        [simplify.
+         rewrite > H.
+         reflexivity.
+        |assumption
+        ]
+      |assumption
+      ]
+    |intro.
+     rewrite > false_to_pi_p_Sn
+      [rewrite > false_to_sigma_p_Sn
+        [simplify.assumption
+        |assumption
+        ]
+      |assumption
+      ]
+    ]
+  ]
+qed.
+
+theorem exp_sigma_p1: \forall n,a,p,f. 
+pi_p n p (\lambda x.(exp a (f x))) = (exp a (sigma_p n p f)).
+intros.
+elim n
+  [reflexivity
+  |apply (bool_elim ? (p n1))
+    [intro.
+     rewrite > true_to_pi_p_Sn
+      [rewrite > true_to_sigma_p_Sn
+        [simplify.
+         rewrite > H.
+         rewrite > exp_plus_times.
+         reflexivity.
+        |assumption
+        ]
+      |assumption
+      ]
+    |intro.
+     rewrite > false_to_pi_p_Sn
+      [rewrite > false_to_sigma_p_Sn
+        [simplify.assumption
+        |assumption
+        ]
+      |assumption
+      ]
+    ]
+  ]
+qed.
+
+theorem times_pi_p: \forall n,p,f,g. 
+pi_p n p (\lambda x.f x*g x) = pi_p n p f * pi_p n p  g. 
+intros.
+elim n
+  [simplify.reflexivity
+  |apply (bool_elim ? (p n1))
+    [intro.
+     rewrite > true_to_pi_p_Sn
+      [rewrite > true_to_pi_p_Sn
+        [rewrite > true_to_pi_p_Sn
+          [rewrite > H.autobatch
+          |assumption
+          ]
+        |assumption
+        ]
+      |assumption
+      ]
+    |intro.
+     rewrite > false_to_pi_p_Sn
+      [rewrite > false_to_pi_p_Sn
+        [rewrite > false_to_pi_p_Sn;assumption
+        |assumption
+        ]
+      |assumption
+      ]
+    ]
+  ]
+qed.
+
+theorem pi_p_SO: \forall n,p. 
+pi_p n p (\lambda i.S O) = S O.
+intros.elim n
+  [reflexivity
+  |simplify.elim (p n1)
+    [simplify.rewrite < plus_n_O.assumption
+    |simplify.assumption
+    ]
+  ]
+qed.
+
+theorem exp_pi_p: \forall n,m,p,f. 
+pi_p n p (\lambda x.exp (f x) m) = exp (pi_p n p f) m.
+intros.
+elim m
+  [simplify.apply pi_p_SO
+  |simplify.
+   rewrite > times_pi_p.
+   rewrite < H.
+   reflexivity
+  ]
+qed.
+
+theorem exp_times_pi_p: \forall n,m,k,p,f. 
+pi_p n p (\lambda x.exp k (m*(f x))) = 
+exp (pi_p n p (\lambda x.exp k (f x))) m.
+intros.
+apply (trans_eq ? ? (pi_p n p (\lambda x.(exp (exp k (f x)) m))))
+  [apply eq_pi_p;intros
+    [reflexivity
+    |apply sym_eq.rewrite > sym_times.
+     apply exp_exp_times
+    ]
+  |apply exp_pi_p
+  ]
+qed.
+
+
+theorem pi_p_knm:
+\forall g: nat \to nat.
+\forall h2:nat \to nat \to nat.
+\forall h11,h12:nat \to nat. 
+\forall k,n,m.
+\forall p1,p21:nat \to bool.
+\forall p22:nat \to nat \to bool.
+(\forall x. x < k \to p1 x = true \to 
+p21 (h11 x) = true ∧ p22 (h11 x) (h12 x) = true
+\land h2 (h11 x) (h12 x) = x 
+\land (h11 x) < n \land (h12 x) < m) \to
+(\forall i,j. i < n \to j < m \to p21 i = true \to p22 i j = true \to 
+p1 (h2 i j) = true \land 
+h11 (h2 i j) = i \land h12 (h2 i j) = j
+\land h2 i j < k) →
+(*
+Pi z < k | p1 z. g z = 
+Pi x < n | p21 x. Pi y < m | p22 x y.g (h2 x y).
+*)
+pi_p k p1 g =
+pi_p n p21 (\lambda x:nat.pi_p m (p22 x) (\lambda y. g (h2 x y))).
+intros.
+unfold pi_p.unfold pi_p.
+apply (iter_p_gen_knm nat (S O) times sym_times assoc_times ? ? ? h11 h12)
+  [intros.apply sym_eq.apply times_n_SO.
+  |assumption
+  |assumption
+  ]
+qed.
+
+theorem pi_p_pi_p: 
+\forall g: nat \to nat \to nat.
+\forall h11,h12,h21,h22: nat \to nat \to nat. 
+\forall n1,m1,n2,m2.
+\forall p11,p21:nat \to bool.
+\forall p12,p22:nat \to nat \to bool.
+(\forall i,j. i < n2 \to j < m2 \to p21 i = true \to p22 i j = true \to 
+p11 (h11 i j) = true \land p12 (h11 i j) (h12 i j) = true
+\land h21 (h11 i j) (h12 i j) = i \land h22 (h11 i j) (h12 i j) = j
+\land h11 i j < n1 \land h12 i j < m1) \to
+(\forall i,j. i < n1 \to j < m1 \to p11 i = true \to p12 i j = true \to 
+p21 (h21 i j) = true \land p22 (h21 i j) (h22 i j) = true
+\land h11 (h21 i j) (h22 i j) = i \land h12 (h21 i j) (h22 i j) = j
+\land (h21 i j) < n2 \land (h22 i j) < m2) \to
+pi_p n1 p11 
+     (\lambda x:nat .pi_p m1 (p12 x) (\lambda y. g x y)) =
+pi_p n2 p21 
+    (\lambda x:nat .pi_p m2 (p22 x)  (\lambda y. g (h11 x y) (h12 x y))).
+intros.
+unfold pi_p.unfold pi_p.
+apply (iter_p_gen_2_eq ? ? ? sym_times assoc_times ? ? ? ? h21 h22)
+  [intros.apply sym_eq.apply times_n_SO.
+  |assumption
+  |assumption
+  ]
+qed.
+
+theorem pi_p_pi_p1: 
+\forall g: nat \to nat \to nat.
+\forall n,m.
+\forall p11,p21:nat \to bool.
+\forall p12,p22:nat \to nat \to bool.
+(\forall x,y. x < n \to y < m \to 
+ (p11 x \land p12 x y) = (p21 y \land p22 y x)) \to
+pi_p n p11 (\lambda x:nat.pi_p m (p12 x) (\lambda y. g x y)) =
+pi_p m p21 (\lambda y:nat.pi_p n (p22 y) (\lambda x. g x y)).
+intros.
+unfold pi_p.unfold pi_p.
+apply (iter_p_gen_iter_p_gen ? ? ? sym_times assoc_times)
+  [intros.apply sym_eq.apply times_n_SO.
+  |assumption
+  ]
+qed. *)
\ No newline at end of file
diff --git a/matita/matita/lib/arithmetics/ord.ma b/matita/matita/lib/arithmetics/ord.ma
new file mode 100644
index 000000000..452106f78
--- /dev/null
+++ b/matita/matita/lib/arithmetics/ord.ma
@@ -0,0 +1,415 @@
+(*
+    ||M||  This file is part of HELM, an Hypertextual, Electronic   
+    ||A||  Library of Mathematics, developed at the Computer Science 
+    ||T||  Department of the University of Bologna, Italy.           
+    ||I||                                                            
+    ||T||  
+    ||A||  
+    \   /  This file is distributed under the terms of the       
+     \ /   GNU General Public License Version 2   
+      V_____________________________________________________________*)
+
+include "arithmetics/exp.ma".
+include "basics/types.ma".
+include "arithmetics/primes.ma".
+include "arithmetics/gcd.ma". 
+(*
+include "arithmetics/nth_prime.ma".
+(* for some properties of divides *)
+*)
+
+let rec p_ord_aux p n m ≝
+  match n \mod m with
+  [ O ⇒ 
+    match p with
+      [ O ⇒ 〈O,n〉
+      | S p ⇒ let 〈q,r〉 ≝ p_ord_aux p (n / m) m in 〈S q,r〉]
+  | S a ⇒ 〈O,n〉].
+ 
+(* p_ord n m = <q,r> if m divides n q times, with remainder r *)
+definition p_ord ≝ λn,m:nat.p_ord_aux n n m.
+
+lemma p_ord_aux_0: ∀n,m.p_ord_aux 0 n m = 〈0,n〉.
+#n #m whd in match (p_ord_aux 0??); cases (n\mod m) normalize //
+qed. 
+
+lemma p_ord_aux_Strue: ∀n,m,p,q,r.
+ n\mod m = 0 → p_ord_aux p (n / m) m = 〈q,r〉 →
+ p_ord_aux (S p) n m = 〈S q,r〉.
+#n #m #p #q #r whd in match (p_ord_aux (S p)??); #H >H 
+#Hord whd in ⊢(??%?); >Hord //
+qed. 
+
+lemma p_ord_aux_false: ∀p,n,m,a.
+ n\mod m = (S a) → p_ord_aux p n m = 〈0,n〉.
+#p #n #m #a cases p whd in match (p_ord_aux ???); 
+  [#H whd in match (p_ord_aux ???); >H // 
+  |#p1 #H whd in match (p_ord_aux ???); >H //
+  ] 
+qed. 
+
+(* the definition of p_ord_aux only makes sense for m>1. 
+   In case m=1 we always end up with the pair 〈p,n〉 *)
+
+lemma p_ord_degenerate: ∀p,n. p_ord_aux p n 1 = 〈p,n〉.
+#p elim p // #p1 #Hind #n
+cut (mod n 1 = 0) [@divides_to_mod_O //] #Hmod
+>(p_ord_aux_Strue … (Hind … ) ) // >(div_mod n 1) in ⊢ (???%);
+>Hmod <plus_n_O <times_n_1 //
+qed.
+
+theorem p_ord_aux_to_exp: ∀p,n,m,q,r. O < m →
+  p_ord_aux p n m = 〈q,r〉 → n = m \sup q *r .
+#p elim p
+  [#n #m @(nat_case (n \mod m))
+    [#Hmod #q #r #posm >p_ord_aux_0 #Hqr destruct (Hqr) //
+    |#a #H #q #r #posm >(p_ord_aux_false … H) #Hqr destruct (Hqr) //
+    ]
+  |#p1 #Hind #n #m @(nat_case (n \mod m))
+    [#Hmod #q #r #posm lapply (refl …(p_ord_aux p1 (n/m) m));
+     cases (p_ord_aux p1 (n/m) m) in ⊢ (???%→?); #q1 #r1 #H1
+     >(p_ord_aux_Strue … Hmod H1) #H destruct (H) whd in match (exp ??);
+     >(div_mod n m) >Hmod <plus_n_O >(Hind … H1) //
+    |#a #H #q #r #posm >(p_ord_aux_false … H) #Hqr destruct (Hqr) //
+    ]
+  ]
+qed.
+
+(* questo va spostato in primes1.ma *)
+theorem p_ord_exp: ∀n,m,i. O < m → n \mod m ≠ O →
+  ∀p. i ≤ p → p_ord_aux p (m \sup i * n) m = 〈i,n〉.
+#n #m #i #posm #Hmod 
+cut (∃a.n\mod m = S a)
+  [@(nat_case (n\mod m)) [#H @False_ind /2/|#a #Hmod1 %{a} //]] * #mod1 #Hmod1
+elim i
+  [#p normalize #posp <plus_n_O @(p_ord_aux_false … Hmod1)
+  |-i #i #Hind #p 
+   @(nat_case p) [#Hp >Hp #Habs @False_ind @(absurd … Habs) //]
+   #p1 #Hp1 #lep1
+   cut (((m \sup (S i)*n) \mod m) = O)
+    [whd in match (exp ??); @divides_to_mod_O // %{(m^i*n)} //] #Hmod2
+   @(p_ord_aux_Strue … Hmod2) <(Hind p1) [2: @le_S_S_to_le //]
+   @eq_f2 // whd in match (exp ??); >associative_times >(commutative_times m)
+   <associative_times >div_times //
+  ]
+qed.
+
+theorem p_ord_aux_to_not_mod_O: ∀p,n,m,q,r. 1<m → O<n → n≤p →
+  p_ord_aux p n m = 〈q,r〉 → r \mod m ≠ O.
+#p elim p
+  [#n #m #q #r #_ #posn #nposn @False_ind @(absurd … posn) /2/  
+  |#p1 #Hind #n #m @(nat_case (n \mod m))
+    [#Hmod #q #r #lt1m #posn #len lapply (refl …(p_ord_aux p1 (n/m) m));
+     cases (p_ord_aux p1 (n/m) m) in ⊢ (???%→?); #q1 #r1 #H1
+     >(p_ord_aux_Strue … Hmod H1) #H destruct (H) whd in match (exp ??);
+     @(Hind … lt1m … H1) 
+      [@(pos_div … posn Hmod) @lt_to_le //
+      |@le_S_S_to_le @(transitive_le … len) @lt_times_to_lt_div
+       >(times_n_1 n) in ⊢ (?%?); @monotonic_lt_times_r //
+      ]
+    |#a #H #q #r #lt1m #posn #posm >(p_ord_aux_false … H) #Hqr destruct (Hqr)
+     >H @sym_not_eq //
+    ]
+  ]
+qed.
+
+theorem p_ord_exp1: ∀p,n,q,r. O < p → p ∤ r →
+  n = p \sup q * r → p_ord n p = 〈q,r〉.
+#p #n #q #r #posp #ndivpr #Hn >Hn -Hn -n @(p_ord_exp … posp)
+  [@(not_to_not … ndivpr) /2/
+  |@(transitive_le ? (p \sup q))
+    [cut (1<p) 
+      [cases (le_to_or_lt_eq … posp) // #eqp1 @False_ind @(absurd ?? ndivpr)
+       <eqp1 % //]
+     #lt1p elim q // -q #q whd in match (exp ??);
+     cases q [#_ normalize <plus_n_O @lt_to_le //]
+     #q1 #Hind @(lt_to_le_to_lt ? ((S q1)*2))
+      [>(times_n_1 (S q1)) in ⊢ (?%?); @monotonic_lt_times_r //
+      |@le_times //
+      ]
+    |>(times_n_1 (p^q)) in ⊢ (?%?); @le_times // 
+     lapply ndivpr -ndivpr cases r // #Habs @False_ind @(absurd ?? Habs) % //
+    ]
+  ]
+qed.
+
+theorem p_ord_to_exp1: ∀p,n,q,r. 1<p → O<n → p_ord n p = 〈q,r〉 → 
+  p ∤ r ∧ n = p \sup q * r.
+#p #n #q #r #lt1p #posn #Hord %
+  [@(not_to_not … (p_ord_aux_to_not_mod_O … lt1p posn (le_n n)… Hord))
+   @divides_to_mod_O @lt_to_le //
+  |@(p_ord_aux_to_exp n …Hord) @lt_to_le //
+  ]
+qed.
+
+theorem eq_p_ord_q_O: ∀p,n,q. p_ord n p = 〈q,O〉 → n=O ∧ q=O.
+#p #n whd in match (p_ord ??);  cases n 
+  [#q cases p normalize [|#q1] #H destruct (H) % //
+  |#n1 #q cases p 
+    [normalize #H destruct (H) 
+    |#p1 cases p1
+      [>p_ord_degenerate #H destruct (H)
+      |#p2 lapply (refl …(p_ord_aux (S n1) (S n1) (S (S p2))));
+       cases (p_ord_aux (S n1) (S n1) (S (S p2))) in ⊢ (???%→?); #qa #ra #H 
+       lapply (p_ord_to_exp1 (S (S p2)) (S n1) … H) //
+       * #_ #H1 >H #H2 @False_ind destruct (H2) <times_n_O in H1; 
+       #Habs destruct (Habs)
+      ]
+    ]
+  ]
+qed.
+
+theorem p_ord_times: ∀p,a,b,qa,ra,qb,rb. prime p → O < a → O < b 
+ → p_ord a p = 〈qa,ra〉  → p_ord b p = 〈qb,rb〉
+  → p_ord (a*b) p = 〈qa + qb, ra*rb〉.
+#p #a #b #qa #ra #qb #rb #Hprime #posa #posb #porda #pordb 
+cut (1<p) [@prime_to_lt_SO //] #Hp1
+cases (p_ord_to_exp1 ???? Hp1 posa porda) -posa -porda #Hdiva #Ha
+elim (p_ord_to_exp1 ???? Hp1 posb pordb) -posb -pordb #Hdivb #Hb
+@p_ord_exp1 
+  [@lt_to_le //
+  |% #Hdiv cases (divides_times_to_divides ? ? ? Hprime Hdiv)
+   #Habs @absurd /2/
+  |>Ha >Hb -Ha -Hb <associative_times <associative_times // 
+  ]
+qed.
+
+theorem fst_p_ord_times: ∀p,a,b. prime p → O < a → O < b → 
+  fst ?? (p_ord (a*b) p) = (fst ?? (p_ord a p)) + (fst ?? (p_ord b p)).
+#p #a #b #primep #posa #posb
+>(p_ord_times p a b (fst ?? (p_ord a p)) (snd ?? (p_ord a p))
+  (fst ?? (p_ord b p)) (snd ? ? (p_ord b p)) primep posa posb) //
+qed.
+
+theorem p_ord_p: ∀p:nat. 1 < p → p_ord p p = 〈1,1〉.
+#p #ltp1 @p_ord_exp1
+  [@lt_to_le //
+  |% #divp1 @(absurd … ltp1) @le_to_not_lt @divides_to_le //
+  |//
+  ]
+qed.
+
+(* p_ord and divides *)
+theorem divides_to_p_ord: ∀p,a,b,c,d,n,m:nat. O < n → O < m → prime p 
+→ divides n m → p_ord n p = 〈a,b〉 →
+  p_ord m p = 〈c,d〉 → divides b d ∧ a ≤ c.
+#p #a #b #c #d #n #m #posn #posm #primep #divnm #ordn #ordm
+cut (1<p) [@prime_to_lt_SO //] #Hposp
+cases (p_ord_to_exp1 ? ? ? ? Hposp posn ordn) #divn #eqn
+cases (p_ord_to_exp1 ? ? ? ? Hposp posm ordm) #divm #eqm %
+  [@(gcd_1_to_divides_times_to_divides b (exp p c))
+    [cases (le_to_or_lt_eq ?? (le_O_n b)) //
+    |elim c 
+      [>commutative_gcd //
+      |#c0 #Hind @eq_gcd_times_1 
+        [@lt_O_exp @lt_to_le //
+        |@lt_to_le //
+        |@Hind 
+        |>commutative_gcd @prime_to_gcd_1 //
+        ] 
+      ]
+    |@(transitive_divides ? n) [%{(exp p a)} // |<eqm //]
+    ]
+  |@(le_exp_to_le p) //
+   @divides_to_le
+    [@lt_O_exp @lt_to_le // 
+    |@(gcd_1_to_divides_times_to_divides ? d)
+      [@lt_O_exp @lt_to_le // 
+      |elim a
+        [@gcd_SO_n
+        |#a0 #Hind whd in match (exp ??); 
+         >commutative_gcd @eq_gcd_times_1
+          [@lt_O_exp @lt_to_le // 
+          |@lt_to_le //
+          |>commutative_gcd //
+          |>commutative_gcd @prime_to_gcd_1 //
+          ]
+        ]
+      |@(transitive_divides ? n) // %{b} // 
+      ]
+    ]
+  ]
+qed.    
+
+(* p_ord and primes *)
+theorem not_divides_to_p_ord_O: ∀n,i.
+  (nth_prime i) ∤ n → p_ord n (nth_prime i) = 〈O,n〉.
+#n #i #H @p_ord_exp1 //
+qed.
+
+theorem p_ord_O_to_not_divides: ∀n,i,r. O < n →
+  p_ord n (nth_prime i) = 〈O,r〉
+  → (nth_prime i) ∤ n.
+#n #i #r #posn #Hord
+lapply (p_ord_to_exp1 … Hord) // * #H 
+normalize <plus_n_O // 
+qed.
+
+theorem p_ord_to_not_eq_O : ∀n,p,q,r. 1<n →
+  p_ord n (nth_prime p) = 〈q,r〉 → r≠O.
+#n #p #q #r #lt1n #Hord
+cut (O<n) [@lt_to_le //] #posn
+lapply (p_ord_to_exp1 …posn … Hord)
+  [@lt_SO_nth_prime_n 
+  |* #H1 #H2 @(not_to_not …(lt_to_not_eq … posn))
+   #eqr >eqr in H2; //
+  ]
+qed.
+
+definition ord :nat → nat → nat ≝
+  λn,p. fst ?? (p_ord n p).
+
+definition ord_rem :nat → nat → nat ≝
+  λn,p. snd ?? (p_ord n p).
+
+lemma ord_eq: ∀n,p. ord n p = fst ?? (p_ord n p). //
+qed.
+
+lemma ord_rem_eq: ∀n,p. ord_rem n p = snd ?? (p_ord n p). //
+qed.
+
+theorem divides_to_ord: ∀p,n,m:nat. 
+  O < n → O < m → prime p → divides n m 
+  → divides (ord_rem n p) (ord_rem m p) ∧ (ord n p) ≤ (ord m p).  
+#p #n #m #H #H1 #H2 #H3
+@(divides_to_p_ord p ? ? ? ? n m H H1 H2 H3) 
+  [@eq_pair_fst_snd|@eq_pair_fst_snd]
+qed.
+
+theorem divides_to_divides_ord_rem: ∀p,n,m:nat. 
+O < n → O < m → prime p → divides n m →
+  divides (ord_rem n p) (ord_rem m p).
+#p #n #m #H #H1 #H2 #H3 cases (divides_to_ord p n m H H1 H2 H3) // 
+qed.
+
+theorem divides_to_le_ord: ∀p,n,m:nat. 
+O < n → O < m → prime p → divides n m →
+  ord n p ≤ ord m p.  
+#p #n #m #H #H1 #H2 #H3 cases (divides_to_ord p n m H H1 H2 H3) //
+qed.
+
+theorem exp_ord: \forall p,n. 1 < p → O < n → 
+  n = p \sup (ord n p) * (ord_rem n p).
+#p #n #H #H1
+cases (p_ord_to_exp1 p n (ord n p) (ord_rem n p) H H1 ?)
+  [// |@eq_pair_fst_snd]
+qed.
+
+theorem divides_ord_rem: ∀p,n. 1 < p → O < n 
+  → divides (ord_rem n p) n. 
+#p #n #H #H1 %{(p \sup (ord n p))} >commutative_times @exp_ord // 
+qed.
+
+theorem lt_O_ord_rem: ∀p,n. 1 < p → O < n → O < ord_rem n p. 
+#p #n #H #H1 
+cases (le_to_or_lt_eq … (le_O_n (ord_rem n p))) //
+#remO lapply(divides_ord_rem ?? H H1) <remO -remO #Hdiv0  
+@False_ind @(absurd (0=n)) [cases Hdiv0 // | @lt_to_not_eq //]
+qed.
+
+(* properties of ord e ord_rem *)
+
+theorem ord_times: ∀p,m,n.O<m → O<n → prime p →
+  ord (m*n) p = ord m p+ord n p.
+#p #m #n #H #H1 #H2 
+lapply (p_ord_times ??? (ord m p) (ord_rem m p) (ord n p) (ord_rem n p) H2 H H1 
+  (eq_pair_fst_snd …) (eq_pair_fst_snd …)) #H3
+  @(eq_f … (fst …) … H3)
+qed.
+
+theorem ord_exp: ∀p,m. 1 < p → ord (exp p m) p = m.
+#p #m #H >ord_eq >(p_ord_exp1 p (exp p m) m (S O)) //
+  [@(not_to_not … (lt_to_not_le … H)) @divides_to_le //
+  |@lt_to_le // 
+  ]
+qed.
+
+theorem not_divides_to_ord_O: 
+∀p,m. prime p → p ∤ m → ord m p = O.
+#p #m #H #H1 >ord_eq >(p_ord_exp1 p m O m) // @prime_to_lt_O //
+qed.
+
+theorem ord_O_to_not_divides: ∀p,m. O < m → prime p → 
+  ord m p = O → p ∤ m.
+#p #m #H #H1 #H2 
+lapply (p_ord_to_exp1 p m (ord m p) (ord_rem m p) … H … (eq_pair_fst_snd …))
+  [@prime_to_lt_SO //
+  |* #H3 >H2 >commutative_times <times_n_1 //  
+  ]
+qed.
+
+theorem divides_to_not_ord_O: 
+∀p,m. O < m → prime p → divides p m →
+  ord m p ≠ O.
+#p #m #H #H1 #H2 % #H3 @(absurd … H2) @(ord_O_to_not_divides ? ? H H1 H3)
+qed.
+
+theorem not_ord_O_to_divides: 
+∀p,m. O < m → prime p → (ord m p ≠ O) → divides p m.
+#p #m #H #H1 #H2  >(exp_ord p m) in ⊢ (??%);
+  [@(transitive_divides ? (exp p (ord m p)))
+    [lapply H2 cases (ord m p) 
+      [* #H3 @False_ind @H3 // 
+      |#a #_ normalize % // 
+      ]
+    |%{(ord_rem m p)} //
+    ]
+  |//
+  |@prime_to_lt_SO //
+  ]
+qed.
+
+theorem not_divides_ord_rem: ∀m,p.O< m → 1 < p →
+  p ∤  (ord_rem m p).
+#m #p #H #H1 
+lapply (p_ord_to_exp1 p m (ord m p) (ord_rem m p) ?? (eq_pair_fst_snd …)) // *
+#H2 #H3 @H2
+qed.
+
+theorem ord_ord_rem: ∀p,q,m. O < m → prime p → prime q →q < p → 
+  ord (ord_rem m p) q = ord m q.
+#p #q #m #H #H1 #H2 #H3 >(exp_ord p m) in ⊢ (???(?%?));
+  [>(ord_times … H2)
+    [>not_divides_to_ord_O in ⊢ (???(?%?)); //
+     @(not_to_not … (lt_to_not_eq ? ? H3))
+     @(divides_exp_to_eq ? ? ? H2 H1)
+    |@lt_O_ord_rem // @prime_to_lt_SO //
+    |@lt_O_exp @prime_to_lt_O //
+    ]
+  |//
+  |@prime_to_lt_SO //
+  ]
+qed.
+
+theorem lt_ord_rem: ∀n,m. prime n → O < m →
+  divides n m → ord_rem m n < m.
+#n #m #H #H1 #H2 
+cases (le_to_or_lt_eq (ord_rem m n) m ?) 
+  [//
+  |#Hm @False_ind <Hm in H2; #Habs @(absurd ? Habs)
+   @not_divides_ord_rem // @prime_to_lt_SO //
+  |@divides_to_le //
+   @divides_ord_rem // @prime_to_lt_SO //
+  ]
+qed.
+
+(* p_ord_inv may be used to encode the pair ord and rem into 
+   a single natural number. *)
+ 
+definition p_ord_inv ≝ λp,m,x. 
+  let 〈q,r〉 ≝ p_ord x p in r*m+q.
+  
+theorem  eq_p_ord_inv: ∀p,m,x.
+  p_ord_inv p m x = (ord_rem x p)*m+(ord x p).
+#p #m #x normalize cases(p_ord_aux x x p) // 
+qed.
+
+theorem div_p_ord_inv: 
+∀p,m,x. ord x p < m → p_ord_inv p m x / m = ord_rem x p.
+#p #m #x >eq_p_ord_inv @div_plus_times
+qed.
+
+theorem mod_p_ord_inv: 
+∀p,m,x. ord x p < m → p_ord_inv p m x \mod m = ord x p.
+#p #m #x >eq_p_ord_inv @mod_plus_times
+qed.