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authorGravatar desmettr <desmettr@85f007b7-540e-0410-9357-904b9bb8a0f7>2003-01-21 16:06:20 +0000
committerGravatar desmettr <desmettr@85f007b7-540e-0410-9357-904b9bb8a0f7>2003-01-21 16:06:20 +0000
commit92bac4d9048a189113469516744db34af82cc421 (patch)
tree70f19f936cc3b630a9bb6d08223347bfbe756eb5 /theories/Reals/AltSeries.v
parent785771ebd3f16778712828bee0aba79bb01e6525 (diff)
Renommage dans AltSeries.v
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@3558 85f007b7-540e-0410-9357-904b9bb8a0f7
Diffstat (limited to 'theories/Reals/AltSeries.v')
-rw-r--r--theories/Reals/AltSeries.v41
1 files changed, 19 insertions, 22 deletions
diff --git a/theories/Reals/AltSeries.v b/theories/Reals/AltSeries.v
index c5c4ec38a..c5e1e0ba5 100644
--- a/theories/Reals/AltSeries.v
+++ b/theories/Reals/AltSeries.v
@@ -17,10 +17,9 @@ Require Max.
(**********)
Definition tg_alt [Un:nat->R] : nat->R := [i:nat]``(pow (-1) i)*(Un i)``.
-Definition positivity_sui [Un:nat->R] : Prop := (n:nat)``0<=(Un n)``.
+Definition positivity_seq [Un:nat->R] : Prop := (n:nat)``0<=(Un n)``.
-(* Croissance des sommes partielles impaires *)
-Lemma CV_ALT_step1 : (Un:nat->R) (Un_decreasing Un) -> (Un_growing [N:nat](sum_f_R0 (tg_alt Un) (S (mult (2) N)))).
+Lemma CV_ALT_step0 : (Un:nat->R) (Un_decreasing Un) -> (Un_growing [N:nat](sum_f_R0 (tg_alt Un) (S (mult (2) N)))).
Intros; Unfold Un_growing; Intro.
Cut (mult (S (S O)) (S n)) = (S (S (mult (2) n))).
Intro; Rewrite H0.
@@ -35,8 +34,7 @@ Cut (n:nat) (S n)=(plus n (1)); [Intro | Intro; Ring].
Rewrite (H0 n); Rewrite (H0 (S (mult (2) n))); Rewrite (H0 (mult (2) n)); Ring.
Qed.
-(* Décroissance des sommes partielles paires *)
-Lemma CV_ALT_step1_bis : (Un:nat->R) (Un_decreasing Un) -> (Un_decreasing [N:nat](sum_f_R0 (tg_alt Un) (mult (2) N))).
+Lemma CV_ALT_step1 : (Un:nat->R) (Un_decreasing Un) -> (Un_decreasing [N:nat](sum_f_R0 (tg_alt Un) (mult (2) N))).
Intros; Unfold Un_decreasing; Intro.
Cut (mult (S (S O)) (S n)) = (S (S (mult (2) n))).
Intro; Rewrite H0; Do 2 Rewrite tech5; Repeat Rewrite Rplus_assoc.
@@ -51,7 +49,7 @@ Rewrite (H0 n); Rewrite (H0 (S (mult (2) n))); Rewrite (H0 (mult (2) n)); Ring.
Qed.
(**********)
-Lemma CV_ALT_step2 : (Un:nat->R;N:nat) (Un_decreasing Un) -> (positivity_sui Un) -> (Rle (sum_f_R0 [i:nat](tg_alt Un (S i)) (S (mult (2) N))) R0).
+Lemma CV_ALT_step2 : (Un:nat->R;N:nat) (Un_decreasing Un) -> (positivity_seq Un) -> (Rle (sum_f_R0 [i:nat](tg_alt Un (S i)) (S (mult (2) N))) R0).
Intros; Induction N.
Simpl; Unfold tg_alt; Simpl; Rewrite Rmult_1r.
Replace ``-1* -1*(Un (S (S O)))`` with (Un (S (S O))); [Idtac | Ring].
@@ -75,7 +73,7 @@ Apply INR_eq; Repeat Rewrite S_INR; Do 2 Rewrite mult_INR; Repeat Rewrite S_INR;
Qed.
(* A more general inequality *)
-Lemma CV_ALT_step3 : (Un:nat->R;N:nat) (Un_decreasing Un) -> (positivity_sui Un) -> (Rle (sum_f_R0 [i:nat](tg_alt Un (S i)) N) R0).
+Lemma CV_ALT_step3 : (Un:nat->R;N:nat) (Un_decreasing Un) -> (positivity_seq Un) -> (Rle (sum_f_R0 [i:nat](tg_alt Un (S i)) N) R0).
Intros; Induction N.
Simpl; Unfold tg_alt; Simpl; Rewrite Rmult_1r.
Apply Rle_anti_compatibility with (Un (S O)).
@@ -99,7 +97,7 @@ Apply CV_ALT_step2; Assumption.
Qed.
(**********)
-Lemma CV_ALT_step4 : (Un:nat->R) (Un_decreasing Un) -> (positivity_sui Un) -> (majoree [N:nat](sum_f_R0 (tg_alt Un) (S (mult (2) N)))).
+Lemma CV_ALT_step4 : (Un:nat->R) (Un_decreasing Un) -> (positivity_seq Un) -> (majoree [N:nat](sum_f_R0 (tg_alt Un) (S (mult (2) N)))).
Intros; Unfold majoree; Unfold bound.
Exists ``(Un O)``.
Unfold is_upper_bound; Intros; Elim H1; Intros.
@@ -112,10 +110,10 @@ Unfold tg_alt; Simpl; Ring.
Apply lt_O_Sn.
Qed.
-(* Ceci donne quasiment le résultat sur la convergence des séries alternées *)
-Lemma CV_ALT : (Un:nat->R) (Un_decreasing Un) -> (positivity_sui Un) -> (Un_cv Un R0) -> (sigTT R [l:R](Un_cv [N:nat](sum_f_R0 (tg_alt Un) N) l)).
+(* This lemma gives an interesting result about alternated series *)
+Lemma CV_ALT : (Un:nat->R) (Un_decreasing Un) -> (positivity_seq Un) -> (Un_cv Un R0) -> (sigTT R [l:R](Un_cv [N:nat](sum_f_R0 (tg_alt Un) N) l)).
Intros.
-Assert H2 := (CV_ALT_step1 ? H).
+Assert H2 := (CV_ALT_step0 ? H).
Assert H3 := (CV_ALT_step4 ? H H0).
Assert X := (growing_cv ? H2 H3).
Elim X; Intros.
@@ -161,28 +159,27 @@ Assumption.
Qed.
(************************************************)
-(* Théorème de convergence des séries alternées *)
+(* Convergence of alternated series *)
(* *)
-(* Applications: PI, cos, sin... *)
+(* Applications: PI, cos, sin *)
(************************************************)
-Theorem Series_Alternees : (Un:nat->R) (Un_decreasing Un) -> (Un_cv Un R0) -> (sigTT R [l:R](Un_cv [N:nat](sum_f_R0 (tg_alt Un) N) l)).
+Theorem alternated_series : (Un:nat->R) (Un_decreasing Un) -> (Un_cv Un R0) -> (sigTT R [l:R](Un_cv [N:nat](sum_f_R0 (tg_alt Un) N) l)).
Intros; Apply CV_ALT.
Assumption.
-Unfold positivity_sui; Apply decreasing_ineq; Assumption.
+Unfold positivity_seq; Apply decreasing_ineq; Assumption.
Assumption.
Qed.
-(* Encadrement de la limite par les sommes partielles *)
-Theorem sommes_partielles_ineq : (Un:nat->R;l:R;N:nat) (Un_decreasing Un) -> (Un_cv Un R0) -> (Un_cv [N:nat](sum_f_R0 (tg_alt Un) N) l) -> ``(sum_f_R0 (tg_alt Un) (S (mult (S (S O)) N)))<=l<=(sum_f_R0 (tg_alt Un) (mult (S (S O)) N))``.
+Theorem alternated_series_ineq : (Un:nat->R;l:R;N:nat) (Un_decreasing Un) -> (Un_cv Un R0) -> (Un_cv [N:nat](sum_f_R0 (tg_alt Un) N) l) -> ``(sum_f_R0 (tg_alt Un) (S (mult (S (S O)) N)))<=l<=(sum_f_R0 (tg_alt Un) (mult (S (S O)) N))``.
Intros.
Cut (Un_cv [N:nat](sum_f_R0 (tg_alt Un) (mult (2) N)) l).
Cut (Un_cv [N:nat](sum_f_R0 (tg_alt Un) (S (mult (2) N))) l).
Intros; Split.
Apply (growing_ineq [N:nat](sum_f_R0 (tg_alt Un) (S (mult (2) N)))).
-Apply CV_ALT_step1; Assumption.
+Apply CV_ALT_step0; Assumption.
Assumption.
Apply (decreasing_ineq [N:nat](sum_f_R0 (tg_alt Un) (mult (2) N))).
-Apply CV_ALT_step1_bis; Assumption.
+Apply CV_ALT_step1; Assumption.
Assumption.
Unfold Un_cv; Unfold R_dist; Unfold Un_cv in H1; Unfold R_dist in H1; Intros.
Elim (H1 eps H2); Intros.
@@ -209,7 +206,7 @@ Assumption.
Qed.
(************************************)
-(* Application : construction de PI *)
+(* Application : construction of PI *)
(************************************)
Definition PI_tg := [n:nat]``/(INR (plus (mult (S (S O)) n) (S O)))``.
@@ -328,7 +325,7 @@ Elim H1; Intros; Assumption.
Qed.
Lemma exist_PI : (sigTT R [l:R](Un_cv [N:nat](sum_f_R0 (tg_alt PI_tg) N) l)).
-Apply Series_Alternees.
+Apply alternated_series.
Apply PI_tg_decreasing.
Apply PI_tg_cv.
Qed.
@@ -338,7 +335,7 @@ Definition PI : R := (Rmult ``4`` (Cases exist_PI of (existTT a b) => a end)).
(* We can get an approximation of PI with the following inequality *)
Lemma PI_ineq : (N:nat) ``(sum_f_R0 (tg_alt PI_tg) (S (mult (S (S O)) N)))<=PI/4<=(sum_f_R0 (tg_alt PI_tg) (mult (S (S O)) N))``.
-Intro; Apply sommes_partielles_ineq.
+Intro; Apply alternated_series_ineq.
Apply PI_tg_decreasing.
Apply PI_tg_cv.
Unfold PI; Case exist_PI; Intro.