aboutsummaryrefslogtreecommitdiffhomepage
path: root/theories/Reals/Rbasic_fun.v
blob: d8c2d62f1b27b7ad1d7ee9610ae421c036cca405 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
(***********************************************************************)
(*  v      *   The Coq Proof Assistant  /  The Coq Development Team    *)
(* <O___,, *        INRIA-Rocquencourt  &  LRI-CNRS-Orsay              *)
(*   \VV/  *************************************************************)
(*    //   *      This file is distributed under the terms of the      *)
(*         *       GNU Lesser General Public License Version 2.1       *)
(***********************************************************************)

(*i $Id$ i*)

(*********************************************************)
(*           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_l:(r1,r2,r:R)(Rgt (Rmin r1 r2) r) ->
    ((Rgt r1 r)/\(Rgt r2 r)).
Intros r1 r2 r;Unfold Rmin;Case (total_order_Rle r1 r2);Intros.
Split.
Assumption.
Unfold Rgt;Unfold Rgt in H;Exact (Rlt_le_trans r r1 r2 H r0).
Split.
Generalize (not_Rle r1 r2 n);Intro;Exact (Rgt_trans r1 r2 r H0 H).
Assumption.
Save.

(*********)
Lemma Rmin_Rgt_r:(r1,r2,r:R)(((Rgt r1 r)/\(Rgt r2 r)) -> 
         (Rgt (Rmin r1 r2) r)).
Intros;Unfold Rmin;Case (total_order_Rle r1 r2);Elim H;Clear H;Intros;
 Assumption.
Save.

(*********)
Lemma Rmin_Rgt:(r1,r2,r:R)(Rgt (Rmin r1 r2) r)<->
    ((Rgt r1 r)/\(Rgt r2 r)).
Intros; Split.
Exact (Rmin_Rgt_l r1 r2 r).
Exact (Rmin_Rgt_r r1 r2 r).
Save.

(*******************************)
(*           Rmax              *)
(*******************************)

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

(*********)
Lemma Rmax_Rle:(r1,r2,r:R)(Rle r (Rmax r1 r2))<->
    ((Rle r r1)\/(Rle r r2)).
Intros;Split.
Unfold Rmax;Case (total_order_Rle r1 r2);Intros;Auto.
Intro;Unfold Rmax;Case (total_order_Rle r1 r2);Elim H;Clear H;Intros;Auto.
Apply (Rle_trans r r1 r2);Auto.
Generalize (not_Rle r1 r2 n);Clear n;Intro;Unfold Rgt in H0;
 Apply (Rlt_le r r1 (Rle_lt_trans r r2 r1 H H0)).
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 a).
Left;Fold (Rgt R0 r);Apply (not_Rle R0 r b).
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_R1: (Rabsolu R1)==R1.
Unfold Rabsolu; Case (case_Rabsolu R1); Auto with real.
Intros H; Absurd ``1 < 0``;Auto with real.
Save.

(*********)
Lemma Rabsolu_no_R0:(r:R)~r==R0->~(Rabsolu r)==R0.
Intros;Unfold Rabsolu;Case (case_Rabsolu r);Intro;Auto.
Apply Ropp_neq;Auto.
Save.

(*********)
Lemma Rabsolu_left: (r:R)(Rlt r R0)->((Rabsolu r) == (Ropp r)).
Intros;Unfold Rabsolu;Case (case_Rabsolu r);Trivial;Intro;Absurd (Rge r R0).
Exact (Rlt_ge_not r R0 H).
Assumption.
Save.

(*********)
Lemma Rabsolu_right: (r:R)(Rge r R0)->((Rabsolu r) == r).
Intros;Unfold Rabsolu;Case (case_Rabsolu r);Intro.
Absurd (Rge r R0).
Exact (Rlt_ge_not r R0 r0).
Assumption.
Trivial.
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_eq:(x:R)(Rle R0 x)->(Rabsolu x)==x.
Intros;Unfold Rabsolu;Case (case_Rabsolu x);Intro;
 [Generalize (Rle_not R0 x r);Intro;ElimType False;Auto|Trivial].
Save.

(*********)
Lemma Rabsolu_Rabsolu:(x:R)(Rabsolu (Rabsolu x))==(Rabsolu x).
Intro;Apply (Rabsolu_pos_eq (Rabsolu x) (Rabsolu_pos x)).
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_Rinv:(r:R)(~r==R0)->(Rabsolu (Rinv r))==
                                  (Rinv (Rabsolu r)).
Intro;Unfold Rabsolu;Case (case_Rabsolu r);
 Case (case_Rabsolu (Rinv r));Auto;Intros.
Apply Ropp_Rinv;Auto.
Generalize (Rlt_Rinv2 r r1);Intro;Unfold Rge in r0;Elim r0;Intros.
Unfold Rgt in H1;Generalize (Rlt_antisym R0 (Rinv r) H1);Intro; 
 ElimType False;Auto.
Generalize 
  (imp_not_Req (Rinv r) R0 
   (or_introl (Rlt (Rinv r) R0) (Rgt (Rinv r) R0) H0));Intro;
 ElimType False;Auto.
Unfold Rge in r1;Elim r1;Clear r1;Intro.
Unfold Rgt in H0;Generalize (Rlt_antisym R0 (Rinv r)  
     (Rlt_Rinv r H0));Intro;ElimType False;Auto.
ElimType False;Auto.
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.

(*********)
Lemma Rabsolu_triang_inv:(a,b:R)(Rle (Rminus (Rabsolu a) (Rabsolu b))
                                     (Rabsolu (Rminus a b))).
Intros;
 Apply (Rle_anti_compatibility (Rabsolu b)
        (Rminus (Rabsolu a) (Rabsolu b)) (Rabsolu (Rminus a b)));
 Unfold Rminus;
 Rewrite <- (Rplus_assoc (Rabsolu b) (Rabsolu a) (Ropp (Rabsolu b)));
 Rewrite (Rplus_sym (Rabsolu b) (Rabsolu a));
 Rewrite (Rplus_assoc (Rabsolu a) (Rabsolu b) (Ropp (Rabsolu b)));
 Rewrite (Rplus_Ropp_r (Rabsolu b));
 Rewrite (proj1 ? ? (Rplus_ne (Rabsolu a)));
 Replace (Rabsolu a) with (Rabsolu (Rplus a R0)).
 Rewrite <- (Rplus_Ropp_r b);
 Rewrite <- (Rplus_assoc a b (Ropp b)); 
 Rewrite (Rplus_sym a b);
 Rewrite (Rplus_assoc b a (Ropp b)).
 Exact (Rabsolu_triang b (Rplus a (Ropp b))).
 Rewrite (proj1 ? ? (Rplus_ne a));Trivial.
Save.

(*********)
Lemma Rabsolu_def1:(x,a:R)(Rlt x a)->(Rlt (Ropp a) x)->(Rlt (Rabsolu x) a).
Unfold Rabsolu;Intros;Case (case_Rabsolu x);Intro.
Generalize (Rlt_Ropp (Ropp a) x H0);Unfold Rgt;Rewrite Ropp_Ropp;Intro;
 Assumption.
Assumption.
Save.

(*********)
Lemma Rabsolu_def2:(x,a:R)(Rlt (Rabsolu x) a)->(Rlt x a)/\(Rlt (Ropp a) x).
Unfold Rabsolu;Intro x;Case (case_Rabsolu x);Intros.
Generalize (Rlt_RoppO x r);Unfold Rgt;Intro;
 Generalize (Rlt_trans R0 (Ropp x) a H0 H);Intro;Split. 
Apply (Rlt_trans x R0 a r H1).
Generalize (Rlt_Ropp (Ropp x) a H);Rewrite (Ropp_Ropp x);Unfold Rgt;Trivial.
Fold (Rgt a x) in H;Generalize (Rgt_ge_trans a x R0 H r);Intro;
 Generalize (Rgt_RoppO a H0);Intro;Fold (Rgt R0 (Ropp a));
 Generalize (Rge_gt_trans x R0 (Ropp a) r H1);Unfold Rgt;Intro;Split;
 Assumption.
Save.