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15 (* This file was automatically generated: do not edit *********************)
17 set "baseuri" "cic:/matita/CoRN-Decl/ftc/RefLemma".
19 (* $Id: RefLemma.v,v 1.7 2004/04/23 10:01:00 lcf Exp $ *)
34 Section Refinement_Lemma.
37 (*#* *The Refinement Lemmas
39 Here we resume the results proved in four different files. The aim is to prove the following result (last part of Theorem 2.9 of Bishop 1967):
41 %\noindent\textbf{%#<b>#Theorem#</b>#%}% Let [f] be a continuous function on a
42 compact interval [[a,b]] with modulus of continuity%\footnote{%# (#From our
43 point of view, the modulus of continuity is simply the proof that [f] is
44 continuous.#)#%}% [omega].
45 Let [P] be a partition of [[a,b]] and [eps [>] Zero] be such that
46 [mesh(P) [<] omega(eps)].
48 %\[\left|S(f,P)-\int_a^bf(x)dx\right|\leq\varepsilon(b-a),\]%#|S(f,P)-∫f(x)dx|≤ε(b-a)#
49 where [S(f,P)] denotes any sum of the function [f] respecting the partition
50 [P] (as previously defined).
52 The proof of this theorem relies on the fact that for any two partitions [P]
53 and [R] of [[a,b]] it is possible to define a partition [Q] which is
54 ``almost'' a common refinement of [P] and [R]---that is, given [eps [>] Zero]
55 it is possible to define [Q] such that for every point [x] of either [P] or
56 [R] there is a point [y] of [Q] such that [|x[-]y| [<] eps].
57 This requires three separate constructions (done in three separate files)
58 which are then properly combined to give the final result. We recommend the
59 reader to ignore this technical constructions.
61 First we prove that if [P] and [R] are both
62 separated (though not necessarily separated from each other) then we can
63 define a partition [P'] arbitrarily close to [P] (that is, such that given
64 [alpha [>] Zero] and [xi [>] Zero] [P'] satisfies both
65 [mesh(P') [<] mesh(P) [+] xi] and for every choice of points [x_i] respecting
66 [P] there is a choice of points [x'_i] respecting [P'] such that
67 [|S(f,P)-S(f,P')| [<] alpha]) that is separated from [R].
69 Then we prove that given any partition [P]
70 and assuming [a [#] b] we can define a partition [P'] arbitrarily close to
71 [P] (in the same sense as above) which is separated.
73 Finally we prove that every two separated
74 partitions [P] and [R] have a common refinement---as every two points in [P]
75 and [R] are apart, we can decide which one is smaller. We use here the
76 technical results about ordering that we proved in the file [IntegralLemmas.v].
78 Using the results from these files, we prove our main lemma in several steps
81 %\begin{convention}% Throughout this section:
82 - [a,b:IR] and [I] denotes [[a,b]];
83 - [F] is a partial function continuous in [I].
88 inline cic:/CoRN/ftc/RefLemma/a.var.
90 inline cic:/CoRN/ftc/RefLemma/b.var.
92 inline cic:/CoRN/ftc/RefLemma/Hab.var.
96 inline cic:/CoRN/ftc/RefLemma/I.con.
100 inline cic:/CoRN/ftc/RefLemma/F.var.
102 inline cic:/CoRN/ftc/RefLemma/contF.var.
104 inline cic:/CoRN/ftc/RefLemma/incF.var.
108 inline cic:/CoRN/ftc/RefLemma/contF'.con.
113 Section First_Refinement_Lemma.
117 This is the first part of the proof of Theorem 2.9.
120 - [P, Q] are partitions of [I] with, respectively, [n] and [m] points;
121 - [Q] is a refinement of [P];
122 - [e] is a positive real number;
123 - [d] is the modulus of continuity of [F] for [e];
124 - the mesh of [P] is less or equal to [d];
125 - [fP] and [fQ] are choices of points respecting the partitions [P] and [Q],
131 inline cic:/CoRN/ftc/RefLemma/e.var.
133 inline cic:/CoRN/ftc/RefLemma/He.var.
137 inline cic:/CoRN/ftc/RefLemma/d.con.
141 inline cic:/CoRN/ftc/RefLemma/m.var.
143 inline cic:/CoRN/ftc/RefLemma/n.var.
145 inline cic:/CoRN/ftc/RefLemma/P.var.
147 inline cic:/CoRN/ftc/RefLemma/HMesh.var.
149 inline cic:/CoRN/ftc/RefLemma/Q.var.
151 inline cic:/CoRN/ftc/RefLemma/Href.var.
153 inline cic:/CoRN/ftc/RefLemma/fP.var.
155 inline cic:/CoRN/ftc/RefLemma/HfP.var.
157 inline cic:/CoRN/ftc/RefLemma/HfP'.var.
159 inline cic:/CoRN/ftc/RefLemma/fQ.var.
161 inline cic:/CoRN/ftc/RefLemma/HfQ.var.
163 inline cic:/CoRN/ftc/RefLemma/HfQ'.var.
167 inline cic:/CoRN/ftc/RefLemma/sub.con.
169 inline cic:/CoRN/ftc/RefLemma/RL_sub_0.con.
171 inline cic:/CoRN/ftc/RefLemma/RL_sub_n.con.
173 inline cic:/CoRN/ftc/RefLemma/RL_sub_mon.con.
175 inline cic:/CoRN/ftc/RefLemma/RL_sub_mon'.con.
177 inline cic:/CoRN/ftc/RefLemma/RL_sub_hyp.con.
179 inline cic:/CoRN/ftc/RefLemma/RL_sub_S.con.
181 inline cic:/CoRN/ftc/RefLemma/H.con.
183 inline cic:/CoRN/ftc/RefLemma/H'.con.
185 inline cic:/CoRN/ftc/RefLemma/H0.con.
187 inline cic:/CoRN/ftc/RefLemma/RL_sub_SS.con.
189 inline cic:/CoRN/ftc/RefLemma/RL_h.con.
191 inline cic:/CoRN/ftc/RefLemma/RL_g.con.
193 inline cic:/CoRN/ftc/RefLemma/ref_calc1.con.
195 inline cic:/CoRN/ftc/RefLemma/ref_calc2.con.
197 inline cic:/CoRN/ftc/RefLemma/ref_calc3.con.
199 inline cic:/CoRN/ftc/RefLemma/ref_calc4.con.
201 inline cic:/CoRN/ftc/RefLemma/ref_calc5.con.
203 inline cic:/CoRN/ftc/RefLemma/ref_calc6.con.
205 inline cic:/CoRN/ftc/RefLemma/ref_calc7.con.
207 inline cic:/CoRN/ftc/RefLemma/ref_calc8.con.
211 inline cic:/CoRN/ftc/RefLemma/first_refinement_lemma.con.
214 End First_Refinement_Lemma.
218 Section Second_Refinement_Lemma.
222 This is inequality (2.6.7).
225 - [P, Q, R] are partitions of [I] with, respectively, [j, n] and [k] points;
226 - [Q] is a common refinement of [P] and [R];
227 - [e, e'] are positive real numbers;
228 - [d, d'] are the moduli of continuity of [F] for [e, e'];
229 - the Mesh of [P] is less or equal to [d];
230 - the Mesh of [R] is less or equal to [d'];
231 - [fP, fQ] and [fR] are choices of points respecting the partitions [P, Q]
232 and [R], respectively.
237 inline cic:/CoRN/ftc/RefLemma/n.var.
239 inline cic:/CoRN/ftc/RefLemma/j.var.
241 inline cic:/CoRN/ftc/RefLemma/k.var.
243 inline cic:/CoRN/ftc/RefLemma/P.var.
245 inline cic:/CoRN/ftc/RefLemma/Q.var.
247 inline cic:/CoRN/ftc/RefLemma/R.var.
249 inline cic:/CoRN/ftc/RefLemma/HrefP.var.
251 inline cic:/CoRN/ftc/RefLemma/HrefR.var.
253 inline cic:/CoRN/ftc/RefLemma/e.var.
255 inline cic:/CoRN/ftc/RefLemma/e'.var.
257 inline cic:/CoRN/ftc/RefLemma/He.var.
259 inline cic:/CoRN/ftc/RefLemma/He'.var.
263 inline cic:/CoRN/ftc/RefLemma/d.con.
265 inline cic:/CoRN/ftc/RefLemma/d'.con.
269 inline cic:/CoRN/ftc/RefLemma/HMeshP.var.
271 inline cic:/CoRN/ftc/RefLemma/HMeshR.var.
273 inline cic:/CoRN/ftc/RefLemma/fP.var.
275 inline cic:/CoRN/ftc/RefLemma/HfP.var.
277 inline cic:/CoRN/ftc/RefLemma/HfP'.var.
279 inline cic:/CoRN/ftc/RefLemma/fR.var.
281 inline cic:/CoRN/ftc/RefLemma/HfR.var.
283 inline cic:/CoRN/ftc/RefLemma/HfR'.var.
285 inline cic:/CoRN/ftc/RefLemma/second_refinement_lemma.con.
288 End Second_Refinement_Lemma.
292 Section Third_Refinement_Lemma.
296 This is an approximation of inequality (2.6.7), but without assuming the existence of a common refinement of [P] and [R].
299 - [P, R] are partitions of [I] with, respectively, [n] and [m] points;
300 - [e, e'] are positive real numbers;
301 - [d, d'] are the moduli of continuity of [F] for [e, e'];
302 - the Mesh of [P] is less than [d];
303 - the Mesh of [R] is less than [d'];
304 - [fP] and [fR] are choices of points respecting the partitions [P] and [R],
306 - [beta] is a positive real number.
311 inline cic:/CoRN/ftc/RefLemma/n.var.
313 inline cic:/CoRN/ftc/RefLemma/m.var.
315 inline cic:/CoRN/ftc/RefLemma/P.var.
317 inline cic:/CoRN/ftc/RefLemma/R.var.
319 inline cic:/CoRN/ftc/RefLemma/e.var.
321 inline cic:/CoRN/ftc/RefLemma/e'.var.
323 inline cic:/CoRN/ftc/RefLemma/He.var.
325 inline cic:/CoRN/ftc/RefLemma/He'.var.
329 inline cic:/CoRN/ftc/RefLemma/d.con.
331 inline cic:/CoRN/ftc/RefLemma/d'.con.
335 inline cic:/CoRN/ftc/RefLemma/HMeshP.var.
337 inline cic:/CoRN/ftc/RefLemma/HMeshR.var.
339 inline cic:/CoRN/ftc/RefLemma/fP.var.
341 inline cic:/CoRN/ftc/RefLemma/HfP.var.
343 inline cic:/CoRN/ftc/RefLemma/HfP'.var.
345 inline cic:/CoRN/ftc/RefLemma/fR.var.
347 inline cic:/CoRN/ftc/RefLemma/HfR.var.
349 inline cic:/CoRN/ftc/RefLemma/HfR'.var.
351 inline cic:/CoRN/ftc/RefLemma/Hab'.var.
353 inline cic:/CoRN/ftc/RefLemma/beta.var.
355 inline cic:/CoRN/ftc/RefLemma/Hbeta.var.
359 inline cic:/CoRN/ftc/RefLemma/alpha.con.
361 inline cic:/CoRN/ftc/RefLemma/RL_alpha.con.
363 inline cic:/CoRN/ftc/RefLemma/csi1.con.
365 inline cic:/CoRN/ftc/RefLemma/RL_csi1.con.
367 inline cic:/CoRN/ftc/RefLemma/delta1.con.
369 inline cic:/CoRN/ftc/RefLemma/RL_delta1.con.
371 inline cic:/CoRN/ftc/RefLemma/P'.con.
373 inline cic:/CoRN/ftc/RefLemma/RL_P'_sep.con.
375 inline cic:/CoRN/ftc/RefLemma/RL_P'_Mesh.con.
377 inline cic:/CoRN/ftc/RefLemma/fP'.con.
379 inline cic:/CoRN/ftc/RefLemma/RL_fP'_in_P'.con.
381 inline cic:/CoRN/ftc/RefLemma/RL_P'_P_sum.con.
383 inline cic:/CoRN/ftc/RefLemma/csi2.con.
385 inline cic:/CoRN/ftc/RefLemma/RL_csi2.con.
387 inline cic:/CoRN/ftc/RefLemma/delta2.con.
389 inline cic:/CoRN/ftc/RefLemma/RL_delta2.con.
391 inline cic:/CoRN/ftc/RefLemma/R'.con.
393 inline cic:/CoRN/ftc/RefLemma/RL_R'_sep.con.
395 inline cic:/CoRN/ftc/RefLemma/RL_R'_Mesh.con.
397 inline cic:/CoRN/ftc/RefLemma/fR'.con.
399 inline cic:/CoRN/ftc/RefLemma/RL_fR'_in_R'.con.
401 inline cic:/CoRN/ftc/RefLemma/RL_R'_R_sum.con.
403 inline cic:/CoRN/ftc/RefLemma/csi3.con.
405 inline cic:/CoRN/ftc/RefLemma/RL_csi3.con.
407 inline cic:/CoRN/ftc/RefLemma/Q.con.
409 inline cic:/CoRN/ftc/RefLemma/RL_Q_Mesh.con.
411 inline cic:/CoRN/ftc/RefLemma/RL_Q_sep.con.
413 inline cic:/CoRN/ftc/RefLemma/fQ.con.
415 inline cic:/CoRN/ftc/RefLemma/RL_fQ_in_Q.con.
417 inline cic:/CoRN/ftc/RefLemma/RL_Q_P'_sum.con.
421 inline cic:/CoRN/ftc/RefLemma/third_refinement_lemma.con.
424 End Third_Refinement_Lemma.
428 Section Fourth_Refinement_Lemma.
433 inline cic:/CoRN/ftc/RefLemma/Fa.con.
435 inline cic:/CoRN/ftc/RefLemma/RL_sum_lemma_aux.con.
440 Finally, this is inequality (2.6.7) exactly as stated (same conventions as
444 inline cic:/CoRN/ftc/RefLemma/n.var.
446 inline cic:/CoRN/ftc/RefLemma/m.var.
448 inline cic:/CoRN/ftc/RefLemma/P.var.
450 inline cic:/CoRN/ftc/RefLemma/R.var.
452 inline cic:/CoRN/ftc/RefLemma/e.var.
454 inline cic:/CoRN/ftc/RefLemma/e'.var.
456 inline cic:/CoRN/ftc/RefLemma/He.var.
458 inline cic:/CoRN/ftc/RefLemma/He'.var.
462 inline cic:/CoRN/ftc/RefLemma/d.con.
464 inline cic:/CoRN/ftc/RefLemma/d'.con.
468 inline cic:/CoRN/ftc/RefLemma/HMeshP.var.
470 inline cic:/CoRN/ftc/RefLemma/HMeshR.var.
472 inline cic:/CoRN/ftc/RefLemma/fP.var.
474 inline cic:/CoRN/ftc/RefLemma/HfP.var.
476 inline cic:/CoRN/ftc/RefLemma/HfP'.var.
478 inline cic:/CoRN/ftc/RefLemma/fR.var.
480 inline cic:/CoRN/ftc/RefLemma/HfR.var.
482 inline cic:/CoRN/ftc/RefLemma/HfR'.var.
486 inline cic:/CoRN/ftc/RefLemma/Hab'.var.
490 inline cic:/CoRN/ftc/RefLemma/fourth_refinement_lemma.con.
493 End Fourth_Refinement_Lemma.
497 Section Main_Refinement_Lemma.
500 (*#* We finish by presenting Theorem 9. *)
502 inline cic:/CoRN/ftc/RefLemma/n.var.
504 inline cic:/CoRN/ftc/RefLemma/m.var.
506 inline cic:/CoRN/ftc/RefLemma/P.var.
508 inline cic:/CoRN/ftc/RefLemma/R.var.
510 inline cic:/CoRN/ftc/RefLemma/e.var.
512 inline cic:/CoRN/ftc/RefLemma/e'.var.
514 inline cic:/CoRN/ftc/RefLemma/He.var.
516 inline cic:/CoRN/ftc/RefLemma/He'.var.
520 inline cic:/CoRN/ftc/RefLemma/d.con.
522 inline cic:/CoRN/ftc/RefLemma/d'.con.
526 inline cic:/CoRN/ftc/RefLemma/HMeshP.var.
528 inline cic:/CoRN/ftc/RefLemma/HMeshR.var.
530 inline cic:/CoRN/ftc/RefLemma/fP.var.
532 inline cic:/CoRN/ftc/RefLemma/HfP.var.
534 inline cic:/CoRN/ftc/RefLemma/HfP'.var.
536 inline cic:/CoRN/ftc/RefLemma/fR.var.
538 inline cic:/CoRN/ftc/RefLemma/HfR.var.
540 inline cic:/CoRN/ftc/RefLemma/HfR'.var.
542 inline cic:/CoRN/ftc/RefLemma/refinement_lemma.con.
545 End Main_Refinement_Lemma.
549 End Refinement_Lemma.