(*********************************************************************)
(*                 The Calculus of Inductive Constructions           *)
(*                                                                   *)
(*                                Projet Coq                         *)
(*                                                                   *)
(*                     INRIA        LRI-CNRS        ENS-CNRS         *)
(*              Rocquencourt         Orsay          Lyon             *)
(*                                                                   *)
(*                                 Coq V6.2                          *)
(*                               May 1st 1998                        *)
(*                                                                   *)
(*********************************************************************)
(*                               Rcompl_lim.v                        *)
(*********************************************************************)

(*********************************************************)
(*           Complements for the real numbers            *)
(*                                                       *)
(*********************************************************)

Require Export R_Ifp.

(*******************************)
(*           Rmin              *)
(*******************************)

(*********)
Definition Rmin :R->R->R:=[x,y:R]
  (Cases (total_order_Rle x y) of 
     leftT   => x
    |rightT  => y
   end).

(*********)
Lemma Rmin_Rgt:(r1,r2,r:R)(Rgt (Rmin r1 r2) r)<->
    ((Rgt r1 r)/\(Rgt r2 r)).
Intros;Split.
Unfold Rmin;Case (total_order_Rle r1 r2);Intros.
Split;Auto.
Unfold Rgt in H;Unfold Rgt;Apply (Rlt_le_trans r r1 r2 H r0).
Split;Auto.
Generalize (not_Rle r1 r2 n);Intro;Clear n;
 Apply (Rgt_trans r1 r2 r H0 H).
Intro;Elim H;Intros;Clear H;Unfold Rmin;Case (total_order_Rle r1 r2);
 Intros;Auto.
Save.

(*******************************)
(*           Rabsolu           *)
(*******************************)

(*********)
Lemma case_Rabsolu:(r:R)(sumboolT (Rlt r R0) (Rge r R0)). 
Intro;Generalize (total_order_Rle R0 r);Intro;Elim X;Intro;Clear X.
Right;Apply (Rle_sym1 R0 r y).
Left;Fold (Rgt R0 r);Apply (not_Rle R0 r y).
Save.

(*********)
Definition Rabsolu:R->R:=
      [r:R](Cases (case_Rabsolu r) of
              (leftT  _) => (Ropp r)
             |(rightT _) => r
            end).

(*********)
Lemma Rabsolu_R0:(Rabsolu R0)==R0.
Unfold Rabsolu;Case (case_Rabsolu R0);Auto;Intro.
Generalize (Rlt_antirefl R0);Intro;ElimType False;Auto.
Save.

(*********)
Lemma Rabsolu_pos:(x:R)(Rle R0 (Rabsolu x)).
Intros;Unfold Rabsolu;Case (case_Rabsolu x);Intro.
Generalize (Rlt_Ropp x R0 r);Intro;Unfold Rgt in H;
 Rewrite Ropp_O in H;Unfold Rle;Left;Assumption.
Apply Rle_sym2;Assumption.
Save.

(*********)
Lemma Rabsolu_pos_lt:(x:R)(~x==R0)->(Rlt R0 (Rabsolu x)).
Intros;Generalize (Rabsolu_pos x);Intro;Unfold Rle in H0;
 Elim H0;Intro;Auto.
ElimType False;Clear H0;Elim H;Clear H;Generalize H1;
 Unfold Rabsolu;Case (case_Rabsolu x);Intros;Auto.
Clear r H1; Generalize (Rplus_plus_r x R0 (Ropp x) H0);
 Rewrite (let (H1,H2)=(Rplus_ne x) in H1);Rewrite (Rplus_Ropp_r x);Trivial.
Save.

(*********)
Lemma Rabsolu_minus_sym:(x,y:R)
 (Rabsolu (Rminus x y))==(Rabsolu (Rminus y x)).
Intros;Unfold Rabsolu;Case (case_Rabsolu (Rminus x y)); 
 Case (case_Rabsolu (Rminus y x));Intros.
 Generalize (Rminus_lt y x r);Generalize (Rminus_lt x y r0);Intros;
 Generalize (Rlt_antisym x y H);Intro;ElimType False;Auto.
Rewrite (Ropp_distr2 x y);Trivial.
Rewrite (Ropp_distr2 y x);Trivial.
Unfold Rge in r r0;Elim r;Elim r0;Intros;Clear r r0.
Generalize (Rgt_RoppO (Rminus x y) H);Rewrite (Ropp_distr2 x y);
 Intro;Unfold Rgt in H0;Generalize (Rlt_antisym R0 (Rminus y x) H0);
 Intro;ElimType False;Auto.
Rewrite (Rminus_eq x y H);Trivial.
Rewrite (Rminus_eq y x H0);Trivial.
Rewrite (Rminus_eq y x H0);Trivial.
Save.

(*********)
Lemma Rabsolu_mult:(x,y:R)
 (Rabsolu (Rmult x y))==(Rmult (Rabsolu x) (Rabsolu y)).
Intros;Unfold Rabsolu;Case (case_Rabsolu (Rmult x y));
 Case (case_Rabsolu x);Case (case_Rabsolu y);Intros;Auto.
Generalize (Rlt_anti_monotony y x R0 r r0);Intro;
 Rewrite (Rmult_Or y) in H;Generalize (Rlt_antisym (Rmult x y) R0 r1);
 Intro;Unfold Rgt in H;ElimType False;Rewrite (Rmult_sym y x) in H;
 Auto.
Rewrite (Ropp_mul1 x y);Trivial. 
Rewrite (Rmult_sym x (Ropp y));Rewrite (Ropp_mul1 y x);
 Rewrite (Rmult_sym  x y);Trivial.
Unfold Rge in r r0;Elim r;Elim r0;Clear r r0;Intros;Unfold Rgt in H H0.
Generalize (Rlt_monotony x R0 y H H0);Intro;Rewrite (Rmult_Or x) in H1;
 Generalize (Rlt_antisym (Rmult x y) R0 r1);Intro;ElimType False;Auto.
Rewrite H in r1;Rewrite (Rmult_Ol y) in r1;Generalize (Rlt_antirefl R0);
 Intro;ElimType False;Auto.
Rewrite H0 in r1;Rewrite (Rmult_Or x) in r1;Generalize (Rlt_antirefl R0);
 Intro;ElimType False;Auto.
Rewrite H0 in r1;Rewrite (Rmult_Or x) in r1;Generalize (Rlt_antirefl R0);
 Intro;ElimType False;Auto.
Rewrite (Ropp_mul2 x y);Trivial.
Unfold Rge in r r1;Elim r;Elim r1;Clear r r1;Intros;Unfold Rgt in H0 H.
Generalize (Rlt_monotony y x R0 H0 r0);Intro;Rewrite (Rmult_Or y) in H1;
 Rewrite (Rmult_sym y x) in H1; 
 Generalize (Rlt_antisym (Rmult x y) R0 H1);Intro;ElimType False;Auto.
Generalize (imp_not_Req x R0 (or_introl (Rlt x R0) (Rgt x R0) r0));
 Generalize (imp_not_Req y R0 (or_intror (Rlt y R0) (Rgt y R0) H0));Intros;
 Generalize (without_div_Od x y H);Intro;Elim H3;Intro;ElimType False;
 Auto.  
Rewrite H0 in H;Rewrite (Rmult_Or x) in H;Unfold Rgt in H;
 Generalize (Rlt_antirefl R0);Intro;ElimType False;Auto.
Rewrite H0;Rewrite (Rmult_Or x);Rewrite (Rmult_Or (Ropp x));Trivial.
Unfold Rge in r0 r1;Elim r0;Elim r1;Clear r0 r1;Intros;Unfold Rgt in H0 H.
Generalize (Rlt_monotony x y R0 H0 r);Intro;Rewrite (Rmult_Or x) in H1;
 Generalize (Rlt_antisym (Rmult x y) R0 H1);Intro;ElimType False;Auto.
Generalize (imp_not_Req y R0 (or_introl (Rlt y R0) (Rgt y R0) r));
 Generalize (imp_not_Req R0 x (or_introl (Rlt R0 x) (Rgt R0 x) H0));Intros;
 Generalize (without_div_Od x y H);Intro;Elim H3;Intro;ElimType False;
 Auto.  
Rewrite H0 in H;Rewrite (Rmult_Ol y) in H;Unfold Rgt in H;
 Generalize (Rlt_antirefl R0);Intro;ElimType False;Auto.
Rewrite H0;Rewrite (Rmult_Ol y);Rewrite (Rmult_Ol (Ropp y));Trivial.
Save.

(*********)
Lemma Rabsolu_triang:(a,b:R)(Rle (Rabsolu (Rplus a b)) 
                                (Rplus (Rabsolu a) (Rabsolu b))).
Intros a b;Unfold Rabsolu;Case (case_Rabsolu (Rplus a b));
 Case (case_Rabsolu a);Case (case_Rabsolu b);Intros.
Apply (eq_Rle (Ropp (Rplus a b)) (Rplus (Ropp a) (Ropp b)));
 Rewrite (Ropp_distr1 a b);Reflexivity.
(**)
Rewrite (Ropp_distr1 a b);
 Apply (Rle_compatibility (Ropp a) (Ropp b) b);
 Unfold Rle;Unfold Rge in r;Elim r;Intro.
Left;Unfold Rgt in H;Generalize (Rlt_compatibility (Ropp b) R0 b H);
 Intro;Elim (Rplus_ne (Ropp b));Intros v w;Rewrite v in H0;Clear v w;
 Rewrite (Rplus_Ropp_l b) in H0;Apply (Rlt_trans (Ropp b) R0 b H0 H).
Right;Rewrite H;Apply Ropp_O.
(**)
Rewrite (Ropp_distr1 a b);
 Rewrite (Rplus_sym (Ropp a) (Ropp b));
 Rewrite (Rplus_sym a (Ropp b));
 Apply (Rle_compatibility (Ropp b) (Ropp a) a);
 Unfold Rle;Unfold Rge in r0;Elim r0;Intro.
Left;Unfold Rgt in H;Generalize (Rlt_compatibility (Ropp a) R0 a H);
 Intro;Elim (Rplus_ne (Ropp a));Intros v w;Rewrite v in H0;Clear v w;
 Rewrite (Rplus_Ropp_l a) in H0;Apply (Rlt_trans (Ropp a) R0 a H0 H).
Right;Rewrite H;Apply Ropp_O.
(**)
ElimType False;Generalize (Rge_plus_plus_r a b R0 r);Intro;
 Elim (Rplus_ne a);Intros v w;Rewrite v in H;Clear v w; 
 Generalize (Rge_trans (Rplus a b) a R0 H r0);Intro;Clear H;
 Unfold Rge in H0;Elim H0;Intro;Clear H0.
Unfold Rgt in H;Generalize (Rlt_antisym (Rplus a b) R0 r1);Intro;Auto.
Absurd (Rplus a b)==R0;Auto.
Apply (imp_not_Req (Rplus a b) R0);Left;Assumption.
(**)
ElimType False;Generalize (Rlt_compatibility a b R0 r);Intro;
 Elim (Rplus_ne a);Intros v w;Rewrite v in H;Clear v w;
 Generalize (Rlt_trans (Rplus a b) a R0 H r0);Intro;Clear H;
 Unfold Rge in r1;Elim r1;Clear r1;Intro.
Unfold Rgt in H;
 Generalize (Rlt_trans (Rplus a b) R0 (Rplus a b) H0 H);Intro;
 Apply (Rlt_antirefl (Rplus a b));Assumption.
Rewrite H in H0;Apply (Rlt_antirefl R0);Assumption.
(**)
Rewrite (Rplus_sym a b);Rewrite (Rplus_sym (Ropp a) b);
 Apply (Rle_compatibility b a (Ropp a));
 Apply (Rminus_le a (Ropp a));Unfold Rminus;Rewrite (Ropp_Ropp a);
 Generalize (Rlt_compatibility a a R0 r0);Clear r r1;Intro;
 Elim (Rplus_ne a);Intros v w;Rewrite v in H;Clear v w;
 Generalize (Rlt_trans (Rplus a a) a R0 H r0);Intro;
 Apply (Rlt_le (Rplus a a) R0 H0).
(**)
Apply (Rle_compatibility a b (Ropp b));
 Apply (Rminus_le b (Ropp b));Unfold Rminus;Rewrite (Ropp_Ropp b);
 Generalize (Rlt_compatibility b b R0 r);Clear r0 r1;Intro;
 Elim (Rplus_ne b);Intros v w;Rewrite v in H;Clear v w;
 Generalize (Rlt_trans (Rplus b b) b R0 H r);Intro;
 Apply (Rlt_le (Rplus b b) R0 H0).
(**)
Unfold Rle;Right;Reflexivity.
Save.

(* $Id: Rbasic_fun.v,v 1.1 1999/07/08 21:55:36 mayero Exp $ *)