diff options
author | herbelin <herbelin@85f007b7-540e-0410-9357-904b9bb8a0f7> | 2003-11-29 17:28:49 +0000 |
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committer | herbelin <herbelin@85f007b7-540e-0410-9357-904b9bb8a0f7> | 2003-11-29 17:28:49 +0000 |
commit | 9a6e3fe764dc2543dfa94de20fe5eec42d6be705 (patch) | |
tree | 77c0021911e3696a8c98e35a51840800db4be2a9 /theories/Reals/PartSum.v | |
parent | 9058fb97426307536f56c3e7447be2f70798e081 (diff) |
Remplacement des fichiers .v ancienne syntaxe de theories, contrib et states par les fichiers nouvelle syntaxe
git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@5027 85f007b7-540e-0410-9357-904b9bb8a0f7
Diffstat (limited to 'theories/Reals/PartSum.v')
-rw-r--r-- | theories/Reals/PartSum.v | 919 |
1 files changed, 523 insertions, 396 deletions
diff --git a/theories/Reals/PartSum.v b/theories/Reals/PartSum.v index 090680cf1..c12aea9df 100644 --- a/theories/Reals/PartSum.v +++ b/theories/Reals/PartSum.v @@ -8,469 +8,596 @@ (*i $Id$ i*) -Require Rbase. -Require Rfunctions. -Require Rseries. -Require Rcomplete. -Require Max. -V7only [ Import nat_scope. Import Z_scope. Import R_scope. ]. +Require Import Rbase. +Require Import Rfunctions. +Require Import Rseries. +Require Import Rcomplete. +Require Import Max. Open Local Scope R_scope. -Lemma tech1 : (An:nat->R;N:nat) ((n:nat)``(le n N)``->``0<(An n)``) -> ``0 < (sum_f_R0 An N)``. -Intros; Induction N. -Simpl; Apply H; Apply le_n. -Simpl; Apply gt0_plus_gt0_is_gt0. -Apply HrecN; Intros; Apply H; Apply le_S; Assumption. -Apply H; Apply le_n. +Lemma tech1 : + forall (An:nat -> R) (N:nat), + (forall n:nat, (n <= N)%nat -> 0 < An n) -> 0 < sum_f_R0 An N. +intros; induction N as [| N HrecN]. +simpl in |- *; apply H; apply le_n. +simpl in |- *; apply Rplus_lt_0_compat. +apply HrecN; intros; apply H; apply le_S; assumption. +apply H; apply le_n. Qed. (* Chasles' relation *) -Lemma tech2 : (An:nat->R;m,n:nat) (lt m n) -> (sum_f_R0 An n) == (Rplus (sum_f_R0 An m) (sum_f_R0 [i:nat]``(An (plus (S m) i))`` (minus n (S m)))). -Intros; Induction n. -Elim (lt_n_O ? H). -Cut (lt m n)\/m=n. -Intro; Elim H0; Intro. -Replace (sum_f_R0 An (S n)) with ``(sum_f_R0 An n)+(An (S n))``; [Idtac | Reflexivity]. -Replace (minus (S n) (S m)) with (S (minus n (S m))). -Replace (sum_f_R0 [i:nat](An (plus (S m) i)) (S (minus n (S m)))) with (Rplus (sum_f_R0 [i:nat](An (plus (S m) i)) (minus n (S m))) (An (plus (S m) (S (minus n (S m)))))); [Idtac | Reflexivity]. -Replace (plus (S m) (S (minus n (S m)))) with (S n). -Rewrite (Hrecn H1). -Ring. -Apply INR_eq; Rewrite S_INR; Rewrite plus_INR; Do 2 Rewrite S_INR; Rewrite minus_INR. -Rewrite S_INR; Ring. -Apply lt_le_S; Assumption. -Apply INR_eq; Rewrite S_INR; Repeat Rewrite minus_INR. -Repeat Rewrite S_INR; Ring. -Apply le_n_S; Apply lt_le_weak; Assumption. -Apply lt_le_S; Assumption. -Rewrite H1; Rewrite <- minus_n_n; Simpl. -Replace (plus n O) with n; [Reflexivity | Ring]. -Inversion H. -Right; Reflexivity. -Left; Apply lt_le_trans with (S m); [Apply lt_n_Sn | Assumption]. +Lemma tech2 : + forall (An:nat -> R) (m n:nat), + (m < n)%nat -> + sum_f_R0 An n = + sum_f_R0 An m + sum_f_R0 (fun i:nat => An (S m + i)%nat) (n - S m). +intros; induction n as [| n Hrecn]. +elim (lt_n_O _ H). +cut ((m < n)%nat \/ m = n). +intro; elim H0; intro. +replace (sum_f_R0 An (S n)) with (sum_f_R0 An n + An (S n)); + [ idtac | reflexivity ]. +replace (S n - S m)%nat with (S (n - S m)). +replace (sum_f_R0 (fun i:nat => An (S m + i)%nat) (S (n - S m))) with + (sum_f_R0 (fun i:nat => An (S m + i)%nat) (n - S m) + + An (S m + S (n - S m))%nat); [ idtac | reflexivity ]. +replace (S m + S (n - S m))%nat with (S n). +rewrite (Hrecn H1). +ring. +apply INR_eq; rewrite S_INR; rewrite plus_INR; do 2 rewrite S_INR; + rewrite minus_INR. +rewrite S_INR; ring. +apply lt_le_S; assumption. +apply INR_eq; rewrite S_INR; repeat rewrite minus_INR. +repeat rewrite S_INR; ring. +apply le_n_S; apply lt_le_weak; assumption. +apply lt_le_S; assumption. +rewrite H1; rewrite <- minus_n_n; simpl in |- *. +replace (n + 0)%nat with n; [ reflexivity | ring ]. +inversion H. +right; reflexivity. +left; apply lt_le_trans with (S m); [ apply lt_n_Sn | assumption ]. Qed. (* Sum of geometric sequences *) -Lemma tech3 : (k:R;N:nat) ``k<>1`` -> (sum_f_R0 [i:nat](pow k i) N)==``(1-(pow k (S N)))/(1-k)``. -Intros; Cut ``1-k<>0``. -Intro; Induction N. -Simpl; Rewrite Rmult_1r; Unfold Rdiv; Rewrite <- Rinv_r_sym. -Reflexivity. -Apply H0. -Replace (sum_f_R0 ([i:nat](pow k i)) (S N)) with (Rplus (sum_f_R0 [i:nat](pow k i) N) (pow k (S N))); [Idtac | Reflexivity]; Rewrite HrecN; Replace ``(1-(pow k (S N)))/(1-k)+(pow k (S N))`` with ``((1-(pow k (S N)))+(1-k)*(pow k (S N)))/(1-k)``. -Apply r_Rmult_mult with ``1-k``. -Unfold Rdiv; Do 2 Rewrite <- (Rmult_sym ``/(1-k)``); Repeat Rewrite <- Rmult_assoc; Rewrite <- Rinv_r_sym; [ Do 2 Rewrite Rmult_1l; Simpl; Ring | Apply H0]. -Apply H0. -Unfold Rdiv; Rewrite Rmult_Rplus_distrl; Rewrite (Rmult_sym ``1-k``); Repeat Rewrite Rmult_assoc; Rewrite <- Rinv_r_sym. -Rewrite Rmult_1r; Reflexivity. -Apply H0. -Apply Rminus_eq_contra; Red; Intro; Elim H; Symmetry; Assumption. +Lemma tech3 : + forall (k:R) (N:nat), + k <> 1 -> sum_f_R0 (fun i:nat => k ^ i) N = (1 - k ^ S N) / (1 - k). +intros; cut (1 - k <> 0). +intro; induction N as [| N HrecN]. +simpl in |- *; rewrite Rmult_1_r; unfold Rdiv in |- *; rewrite <- Rinv_r_sym. +reflexivity. +apply H0. +replace (sum_f_R0 (fun i:nat => k ^ i) (S N)) with + (sum_f_R0 (fun i:nat => k ^ i) N + k ^ S N); [ idtac | reflexivity ]; + rewrite HrecN; + replace ((1 - k ^ S N) / (1 - k) + k ^ S N) with + ((1 - k ^ S N + (1 - k) * k ^ S N) / (1 - k)). +apply Rmult_eq_reg_l with (1 - k). +unfold Rdiv in |- *; do 2 rewrite <- (Rmult_comm (/ (1 - k))); + repeat rewrite <- Rmult_assoc; rewrite <- Rinv_r_sym; + [ do 2 rewrite Rmult_1_l; simpl in |- *; ring | apply H0 ]. +apply H0. +unfold Rdiv in |- *; rewrite Rmult_plus_distr_r; rewrite (Rmult_comm (1 - k)); + repeat rewrite Rmult_assoc; rewrite <- Rinv_r_sym. +rewrite Rmult_1_r; reflexivity. +apply H0. +apply Rminus_eq_contra; red in |- *; intro; elim H; symmetry in |- *; + assumption. Qed. -Lemma tech4 : (An:nat->R;k:R;N:nat) ``0<=k`` -> ((i:nat)``(An (S i))<k*(An i)``) -> ``(An N)<=(An O)*(pow k N)``. -Intros; Induction N. -Simpl; Right; Ring. -Apply Rle_trans with ``k*(An N)``. -Left; Apply (H0 N). -Replace (S N) with (plus N (1)); [Idtac | Ring]. -Rewrite pow_add; Simpl; Rewrite Rmult_1r; Replace ``(An O)*((pow k N)*k)`` with ``k*((An O)*(pow k N))``; [Idtac | Ring]; Apply Rle_monotony. -Assumption. -Apply HrecN. +Lemma tech4 : + forall (An:nat -> R) (k:R) (N:nat), + 0 <= k -> (forall i:nat, An (S i) < k * An i) -> An N <= An 0%nat * k ^ N. +intros; induction N as [| N HrecN]. +simpl in |- *; right; ring. +apply Rle_trans with (k * An N). +left; apply (H0 N). +replace (S N) with (N + 1)%nat; [ idtac | ring ]. +rewrite pow_add; simpl in |- *; rewrite Rmult_1_r; + replace (An 0%nat * (k ^ N * k)) with (k * (An 0%nat * k ^ N)); + [ idtac | ring ]; apply Rmult_le_compat_l. +assumption. +apply HrecN. Qed. -Lemma tech5 : (An:nat->R;N:nat) (sum_f_R0 An (S N))==``(sum_f_R0 An N)+(An (S N))``. -Intros; Reflexivity. +Lemma tech5 : + forall (An:nat -> R) (N:nat), sum_f_R0 An (S N) = sum_f_R0 An N + An (S N). +intros; reflexivity. Qed. -Lemma tech6 : (An:nat->R;k:R;N:nat) ``0<=k`` -> ((i:nat)``(An (S i))<k*(An i)``) -> (Rle (sum_f_R0 An N) (Rmult (An O) (sum_f_R0 [i:nat](pow k i) N))). -Intros; Induction N. -Simpl; Right; Ring. -Apply Rle_trans with (Rplus (Rmult (An O) (sum_f_R0 [i:nat](pow k i) N)) (An (S N))). -Rewrite tech5; Do 2 Rewrite <- (Rplus_sym (An (S N))); Apply Rle_compatibility. -Apply HrecN. -Rewrite tech5 ; Rewrite Rmult_Rplus_distr; Apply Rle_compatibility. -Apply tech4; Assumption. +Lemma tech6 : + forall (An:nat -> R) (k:R) (N:nat), + 0 <= k -> + (forall i:nat, An (S i) < k * An i) -> + sum_f_R0 An N <= An 0%nat * sum_f_R0 (fun i:nat => k ^ i) N. +intros; induction N as [| N HrecN]. +simpl in |- *; right; ring. +apply Rle_trans with (An 0%nat * sum_f_R0 (fun i:nat => k ^ i) N + An (S N)). +rewrite tech5; do 2 rewrite <- (Rplus_comm (An (S N))); + apply Rplus_le_compat_l. +apply HrecN. +rewrite tech5; rewrite Rmult_plus_distr_l; apply Rplus_le_compat_l. +apply tech4; assumption. Qed. -Lemma tech7 : (r1,r2:R) ``r1<>0`` -> ``r2<>0`` -> ``r1<>r2`` -> ``/r1<>/r2``. -Intros; Red; Intro. -Assert H3 := (Rmult_mult_r r1 ? ? H2). -Rewrite <- Rinv_r_sym in H3; [Idtac | Assumption]. -Assert H4 := (Rmult_mult_r r2 ? ? H3). -Rewrite Rmult_1r in H4; Rewrite <- Rmult_assoc in H4. -Rewrite Rinv_r_simpl_m in H4; [Idtac | Assumption]. -Elim H1; Symmetry; Assumption. +Lemma tech7 : forall r1 r2:R, r1 <> 0 -> r2 <> 0 -> r1 <> r2 -> / r1 <> / r2. +intros; red in |- *; intro. +assert (H3 := Rmult_eq_compat_l r1 _ _ H2). +rewrite <- Rinv_r_sym in H3; [ idtac | assumption ]. +assert (H4 := Rmult_eq_compat_l r2 _ _ H3). +rewrite Rmult_1_r in H4; rewrite <- Rmult_assoc in H4. +rewrite Rinv_r_simpl_m in H4; [ idtac | assumption ]. +elim H1; symmetry in |- *; assumption. Qed. -Lemma tech11 : (An,Bn,Cn:nat->R;N:nat) ((i:nat) (An i)==``(Bn i)-(Cn i)``) -> (sum_f_R0 An N)==``(sum_f_R0 Bn N)-(sum_f_R0 Cn N)``. -Intros; Induction N. -Simpl; Apply H. -Do 3 Rewrite tech5; Rewrite HrecN; Rewrite (H (S N)); Ring. +Lemma tech11 : + forall (An Bn Cn:nat -> R) (N:nat), + (forall i:nat, An i = Bn i - Cn i) -> + sum_f_R0 An N = sum_f_R0 Bn N - sum_f_R0 Cn N. +intros; induction N as [| N HrecN]. +simpl in |- *; apply H. +do 3 rewrite tech5; rewrite HrecN; rewrite (H (S N)); ring. Qed. -Lemma tech12 : (An:nat->R;x:R;l:R) (Un_cv [N:nat](sum_f_R0 [i:nat]``(An i)*(pow x i)`` N) l) -> (Pser An x l). -Intros; Unfold Pser; Unfold infinit_sum; Unfold Un_cv in H; Assumption. +Lemma tech12 : + forall (An:nat -> R) (x l:R), + Un_cv (fun N:nat => sum_f_R0 (fun i:nat => An i * x ^ i) N) l -> + Pser An x l. +intros; unfold Pser in |- *; unfold infinit_sum in |- *; unfold Un_cv in H; + assumption. Qed. -Lemma scal_sum : (An:nat->R;N:nat;x:R) (Rmult x (sum_f_R0 An N))==(sum_f_R0 [i:nat]``(An i)*x`` N). -Intros; Induction N. -Simpl; Ring. -Do 2 Rewrite tech5. -Rewrite Rmult_Rplus_distr; Rewrite <- HrecN; Ring. +Lemma scal_sum : + forall (An:nat -> R) (N:nat) (x:R), + x * sum_f_R0 An N = sum_f_R0 (fun i:nat => An i * x) N. +intros; induction N as [| N HrecN]. +simpl in |- *; ring. +do 2 rewrite tech5. +rewrite Rmult_plus_distr_l; rewrite <- HrecN; ring. Qed. -Lemma decomp_sum : (An:nat->R;N:nat) (lt O N) -> (sum_f_R0 An N)==(Rplus (An O) (sum_f_R0 [i:nat](An (S i)) (pred N))). -Intros; Induction N. -Elim (lt_n_n ? H). -Cut (lt O N)\/N=O. -Intro; Elim H0; Intro. -Cut (S (pred N))=(pred (S N)). -Intro; Rewrite <- H2. -Do 2 Rewrite tech5. -Replace (S (S (pred N))) with (S N). -Rewrite (HrecN H1); Ring. -Rewrite H2; Simpl; Reflexivity. -Assert H2 := (O_or_S N). -Elim H2; Intros. -Elim a; Intros. -Rewrite <- p. -Simpl; Reflexivity. -Rewrite <- b in H1; Elim (lt_n_n ? H1). -Rewrite H1; Simpl; Reflexivity. -Inversion H. -Right; Reflexivity. -Left; Apply lt_le_trans with (1); [Apply lt_O_Sn | Assumption]. +Lemma decomp_sum : + forall (An:nat -> R) (N:nat), + (0 < N)%nat -> + sum_f_R0 An N = An 0%nat + sum_f_R0 (fun i:nat => An (S i)) (pred N). +intros; induction N as [| N HrecN]. +elim (lt_irrefl _ H). +cut ((0 < N)%nat \/ N = 0%nat). +intro; elim H0; intro. +cut (S (pred N) = pred (S N)). +intro; rewrite <- H2. +do 2 rewrite tech5. +replace (S (S (pred N))) with (S N). +rewrite (HrecN H1); ring. +rewrite H2; simpl in |- *; reflexivity. +assert (H2 := O_or_S N). +elim H2; intros. +elim a; intros. +rewrite <- p. +simpl in |- *; reflexivity. +rewrite <- b in H1; elim (lt_irrefl _ H1). +rewrite H1; simpl in |- *; reflexivity. +inversion H. +right; reflexivity. +left; apply lt_le_trans with 1%nat; [ apply lt_O_Sn | assumption ]. Qed. -Lemma plus_sum : (An,Bn:nat->R;N:nat) (sum_f_R0 [i:nat]``(An i)+(Bn i)`` N)==``(sum_f_R0 An N)+(sum_f_R0 Bn N)``. -Intros; Induction N. -Simpl; Ring. -Do 3 Rewrite tech5; Rewrite HrecN; Ring. +Lemma plus_sum : + forall (An Bn:nat -> R) (N:nat), + sum_f_R0 (fun i:nat => An i + Bn i) N = sum_f_R0 An N + sum_f_R0 Bn N. +intros; induction N as [| N HrecN]. +simpl in |- *; ring. +do 3 rewrite tech5; rewrite HrecN; ring. Qed. -Lemma sum_eq : (An,Bn:nat->R;N:nat) ((i:nat)(le i N)->(An i)==(Bn i)) -> (sum_f_R0 An N)==(sum_f_R0 Bn N). -Intros; Induction N. -Simpl; Apply H; Apply le_n. -Do 2 Rewrite tech5; Rewrite HrecN. -Rewrite (H (S N)); [Reflexivity | Apply le_n]. -Intros; Apply H; Apply le_trans with N; [Assumption | Apply le_n_Sn]. +Lemma sum_eq : + forall (An Bn:nat -> R) (N:nat), + (forall i:nat, (i <= N)%nat -> An i = Bn i) -> + sum_f_R0 An N = sum_f_R0 Bn N. +intros; induction N as [| N HrecN]. +simpl in |- *; apply H; apply le_n. +do 2 rewrite tech5; rewrite HrecN. +rewrite (H (S N)); [ reflexivity | apply le_n ]. +intros; apply H; apply le_trans with N; [ assumption | apply le_n_Sn ]. Qed. (* Unicity of the limit defined by convergent series *) -Lemma unicity_sum : (An:nat->R;l1,l2:R) (infinit_sum An l1) -> (infinit_sum An l2) -> l1 == l2. -Unfold infinit_sum; Intros. -Case (Req_EM l1 l2); Intro. -Assumption. -Cut ``0<(Rabsolu ((l1-l2)/2))``; [Intro | Apply Rabsolu_pos_lt]. -Elim (H ``(Rabsolu ((l1-l2)/2))`` H2); Intros. -Elim (H0 ``(Rabsolu ((l1-l2)/2))`` H2); Intros. -Pose N := (max x0 x); Cut (ge N x0). -Cut (ge N x). -Intros; Assert H7 := (H3 N H5); Assert H8 := (H4 N H6). -Cut ``(Rabsolu (l1-l2)) <= (R_dist (sum_f_R0 An N) l1) + (R_dist (sum_f_R0 An N) l2)``. -Intro; Assert H10 := (Rplus_lt ? ? ? ? H7 H8); Assert H11 := (Rle_lt_trans ? ? ? H9 H10); Unfold Rdiv in H11; Rewrite Rabsolu_mult in H11. -Cut ``(Rabsolu (/2))==/2``. -Intro; Rewrite H12 in H11; Assert H13 := double_var; Unfold Rdiv in H13; Rewrite <- H13 in H11. -Elim (Rlt_antirefl ? H11). -Apply Rabsolu_right; Left; Change ``0</2``; Apply Rlt_Rinv; Cut ~(O=(2)); [Intro H20; Generalize (lt_INR_0 (2) (neq_O_lt (2) H20)); Unfold INR; Intro; Assumption | Discriminate]. -Unfold R_dist; Rewrite <- (Rabsolu_Ropp ``(sum_f_R0 An N)-l1``); Rewrite Ropp_distr3. -Replace ``l1-l2`` with ``((l1-(sum_f_R0 An N)))+((sum_f_R0 An N)-l2)``; [Idtac | Ring]. -Apply Rabsolu_triang. -Unfold ge; Unfold N; Apply le_max_r. -Unfold ge; Unfold N; Apply le_max_l. -Unfold Rdiv; Apply prod_neq_R0. -Apply Rminus_eq_contra; Assumption. -Apply Rinv_neq_R0; DiscrR. +Lemma uniqueness_sum : + forall (An:nat -> R) (l1 l2:R), + infinit_sum An l1 -> infinit_sum An l2 -> l1 = l2. +unfold infinit_sum in |- *; intros. +case (Req_dec l1 l2); intro. +assumption. +cut (0 < Rabs ((l1 - l2) / 2)); [ intro | apply Rabs_pos_lt ]. +elim (H (Rabs ((l1 - l2) / 2)) H2); intros. +elim (H0 (Rabs ((l1 - l2) / 2)) H2); intros. +pose (N := max x0 x); cut (N >= x0)%nat. +cut (N >= x)%nat. +intros; assert (H7 := H3 N H5); assert (H8 := H4 N H6). +cut (Rabs (l1 - l2) <= R_dist (sum_f_R0 An N) l1 + R_dist (sum_f_R0 An N) l2). +intro; assert (H10 := Rplus_lt_compat _ _ _ _ H7 H8); + assert (H11 := Rle_lt_trans _ _ _ H9 H10); unfold Rdiv in H11; + rewrite Rabs_mult in H11. +cut (Rabs (/ 2) = / 2). +intro; rewrite H12 in H11; assert (H13 := double_var); unfold Rdiv in H13; + rewrite <- H13 in H11. +elim (Rlt_irrefl _ H11). +apply Rabs_right; left; change (0 < / 2) in |- *; apply Rinv_0_lt_compat; + cut (0%nat <> 2%nat); + [ intro H20; generalize (lt_INR_0 2 (neq_O_lt 2 H20)); unfold INR in |- *; + intro; assumption + | discriminate ]. +unfold R_dist in |- *; rewrite <- (Rabs_Ropp (sum_f_R0 An N - l1)); + rewrite Ropp_minus_distr'. +replace (l1 - l2) with (l1 - sum_f_R0 An N + (sum_f_R0 An N - l2)); + [ idtac | ring ]. +apply Rabs_triang. +unfold ge in |- *; unfold N in |- *; apply le_max_r. +unfold ge in |- *; unfold N in |- *; apply le_max_l. +unfold Rdiv in |- *; apply prod_neq_R0. +apply Rminus_eq_contra; assumption. +apply Rinv_neq_0_compat; discrR. Qed. -Lemma minus_sum : (An,Bn:nat->R;N:nat) (sum_f_R0 [i:nat]``(An i)-(Bn i)`` N)==``(sum_f_R0 An N)-(sum_f_R0 Bn N)``. -Intros; Induction N. -Simpl; Ring. -Do 3 Rewrite tech5; Rewrite HrecN; Ring. +Lemma minus_sum : + forall (An Bn:nat -> R) (N:nat), + sum_f_R0 (fun i:nat => An i - Bn i) N = sum_f_R0 An N - sum_f_R0 Bn N. +intros; induction N as [| N HrecN]. +simpl in |- *; ring. +do 3 rewrite tech5; rewrite HrecN; ring. Qed. -Lemma sum_decomposition : (An:nat->R;N:nat) (Rplus (sum_f_R0 [l:nat](An (mult (2) l)) (S N)) (sum_f_R0 [l:nat](An (S (mult (2) l))) N))==(sum_f_R0 An (mult (2) (S N))). -Intros. -Induction N. -Simpl; Ring. -Rewrite tech5. -Rewrite (tech5 [l:nat](An (S (mult (2) l))) N). -Replace (mult (2) (S (S N))) with (S (S (mult (2) (S N)))). -Rewrite (tech5 An (S (mult (2) (S N)))). -Rewrite (tech5 An (mult (2) (S N))). -Rewrite <- HrecN. -Ring. -Apply INR_eq; Do 2 Rewrite S_INR; Do 2 Rewrite mult_INR;Repeat Rewrite S_INR. -Ring. +Lemma sum_decomposition : + forall (An:nat -> R) (N:nat), + sum_f_R0 (fun l:nat => An (2 * l)%nat) (S N) + + sum_f_R0 (fun l:nat => An (S (2 * l))) N = sum_f_R0 An (2 * S N). +intros. +induction N as [| N HrecN]. +simpl in |- *; ring. +rewrite tech5. +rewrite (tech5 (fun l:nat => An (S (2 * l))) N). +replace (2 * S (S N))%nat with (S (S (2 * S N))). +rewrite (tech5 An (S (2 * S N))). +rewrite (tech5 An (2 * S N)). +rewrite <- HrecN. +ring. +apply INR_eq; do 2 rewrite S_INR; do 2 rewrite mult_INR; repeat rewrite S_INR. +ring. Qed. -Lemma sum_Rle : (An,Bn:nat->R;N:nat) ((n:nat)(le n N)->``(An n)<=(Bn n)``) -> ``(sum_f_R0 An N)<=(sum_f_R0 Bn N)``. -Intros. -Induction N. -Simpl; Apply H. -Apply le_n. -Do 2 Rewrite tech5. -Apply Rle_trans with ``(sum_f_R0 An N)+(Bn (S N))``. -Apply Rle_compatibility. -Apply H. -Apply le_n. -Do 2 Rewrite <- (Rplus_sym ``(Bn (S N))``). -Apply Rle_compatibility. -Apply HrecN. -Intros; Apply H. -Apply le_trans with N; [Assumption | Apply le_n_Sn]. +Lemma sum_Rle : + forall (An Bn:nat -> R) (N:nat), + (forall n:nat, (n <= N)%nat -> An n <= Bn n) -> + sum_f_R0 An N <= sum_f_R0 Bn N. +intros. +induction N as [| N HrecN]. +simpl in |- *; apply H. +apply le_n. +do 2 rewrite tech5. +apply Rle_trans with (sum_f_R0 An N + Bn (S N)). +apply Rplus_le_compat_l. +apply H. +apply le_n. +do 2 rewrite <- (Rplus_comm (Bn (S N))). +apply Rplus_le_compat_l. +apply HrecN. +intros; apply H. +apply le_trans with N; [ assumption | apply le_n_Sn ]. Qed. -Lemma sum_Rabsolu : (An:nat->R;N:nat) (Rle (Rabsolu (sum_f_R0 An N)) (sum_f_R0 [l:nat](Rabsolu (An l)) N)). -Intros. -Induction N. -Simpl. -Right; Reflexivity. -Do 2 Rewrite tech5. -Apply Rle_trans with ``(Rabsolu (sum_f_R0 An N))+(Rabsolu (An (S N)))``. -Apply Rabsolu_triang. -Do 2 Rewrite <- (Rplus_sym (Rabsolu (An (S N)))). -Apply Rle_compatibility. -Apply HrecN. +Lemma Rsum_abs : + forall (An:nat -> R) (N:nat), + Rabs (sum_f_R0 An N) <= sum_f_R0 (fun l:nat => Rabs (An l)) N. +intros. +induction N as [| N HrecN]. +simpl in |- *. +right; reflexivity. +do 2 rewrite tech5. +apply Rle_trans with (Rabs (sum_f_R0 An N) + Rabs (An (S N))). +apply Rabs_triang. +do 2 rewrite <- (Rplus_comm (Rabs (An (S N)))). +apply Rplus_le_compat_l. +apply HrecN. Qed. -Lemma sum_cte : (x:R;N:nat) (sum_f_R0 [_:nat]x N) == ``x*(INR (S N))``. -Intros. -Induction N. -Simpl; Ring. -Rewrite tech5. -Rewrite HrecN; Repeat Rewrite S_INR; Ring. +Lemma sum_cte : + forall (x:R) (N:nat), sum_f_R0 (fun _:nat => x) N = x * INR (S N). +intros. +induction N as [| N HrecN]. +simpl in |- *; ring. +rewrite tech5. +rewrite HrecN; repeat rewrite S_INR; ring. Qed. (**********) -Lemma sum_growing : (An,Bn:nat->R;N:nat) ((n:nat)``(An n)<=(Bn n)``)->``(sum_f_R0 An N)<=(sum_f_R0 Bn N)``. -Intros. -Induction N. -Simpl; Apply H. -Do 2 Rewrite tech5. -Apply Rle_trans with ``(sum_f_R0 An N)+(Bn (S N))``. -Apply Rle_compatibility; Apply H. -Do 2 Rewrite <- (Rplus_sym (Bn (S N))). -Apply Rle_compatibility; Apply HrecN. +Lemma sum_growing : + forall (An Bn:nat -> R) (N:nat), + (forall n:nat, An n <= Bn n) -> sum_f_R0 An N <= sum_f_R0 Bn N. +intros. +induction N as [| N HrecN]. +simpl in |- *; apply H. +do 2 rewrite tech5. +apply Rle_trans with (sum_f_R0 An N + Bn (S N)). +apply Rplus_le_compat_l; apply H. +do 2 rewrite <- (Rplus_comm (Bn (S N))). +apply Rplus_le_compat_l; apply HrecN. Qed. (**********) -Lemma Rabsolu_triang_gen : (An:nat->R;N:nat) (Rle (Rabsolu (sum_f_R0 An N)) (sum_f_R0 [i:nat](Rabsolu (An i)) N)). -Intros. -Induction N. -Simpl. -Right; Reflexivity. -Do 2 Rewrite tech5. -Apply Rle_trans with ``(Rabsolu ((sum_f_R0 An N)))+(Rabsolu (An (S N)))``. -Apply Rabsolu_triang. -Do 2 Rewrite <- (Rplus_sym (Rabsolu (An (S N)))). -Apply Rle_compatibility; Apply HrecN. +Lemma Rabs_triang_gen : + forall (An:nat -> R) (N:nat), + Rabs (sum_f_R0 An N) <= sum_f_R0 (fun i:nat => Rabs (An i)) N. +intros. +induction N as [| N HrecN]. +simpl in |- *. +right; reflexivity. +do 2 rewrite tech5. +apply Rle_trans with (Rabs (sum_f_R0 An N) + Rabs (An (S N))). +apply Rabs_triang. +do 2 rewrite <- (Rplus_comm (Rabs (An (S N)))). +apply Rplus_le_compat_l; apply HrecN. Qed. (**********) -Lemma cond_pos_sum : (An:nat->R;N:nat) ((n:nat)``0<=(An n)``) -> ``0<=(sum_f_R0 An N)``. -Intros. -Induction N. -Simpl; Apply H. -Rewrite tech5. -Apply ge0_plus_ge0_is_ge0. -Apply HrecN. -Apply H. +Lemma cond_pos_sum : + forall (An:nat -> R) (N:nat), + (forall n:nat, 0 <= An n) -> 0 <= sum_f_R0 An N. +intros. +induction N as [| N HrecN]. +simpl in |- *; apply H. +rewrite tech5. +apply Rplus_le_le_0_compat. +apply HrecN. +apply H. Qed. (* Cauchy's criterion for series *) -Definition Cauchy_crit_series [An:nat->R] : Prop := (Cauchy_crit [N:nat](sum_f_R0 An N)). +Definition Cauchy_crit_series (An:nat -> R) : Prop := + Cauchy_crit (fun N:nat => sum_f_R0 An N). (* If (|An|) satisfies the Cauchy's criterion for series, then (An) too *) -Lemma cauchy_abs : (An:nat->R) (Cauchy_crit_series [i:nat](Rabsolu (An i))) -> (Cauchy_crit_series An). -Unfold Cauchy_crit_series; Unfold Cauchy_crit. -Intros. -Elim (H eps H0); Intros. -Exists x. -Intros. -Cut (Rle (R_dist (sum_f_R0 An n) (sum_f_R0 An m)) (R_dist (sum_f_R0 [i:nat](Rabsolu (An i)) n) (sum_f_R0 [i:nat](Rabsolu (An i)) m))). -Intro. -Apply Rle_lt_trans with (R_dist (sum_f_R0 [i:nat](Rabsolu (An i)) n) (sum_f_R0 [i:nat](Rabsolu (An i)) m)). -Assumption. -Apply H1; Assumption. -Assert H4 := (lt_eq_lt_dec n m). -Elim H4; Intro. -Elim a; Intro. -Rewrite (tech2 An n m); [Idtac | Assumption]. -Rewrite (tech2 [i:nat](Rabsolu (An i)) n m); [Idtac | Assumption]. -Unfold R_dist. -Unfold Rminus. -Do 2 Rewrite Ropp_distr1. -Do 2 Rewrite <- Rplus_assoc. -Do 2 Rewrite Rplus_Ropp_r. -Do 2 Rewrite Rplus_Ol. -Do 2 Rewrite Rabsolu_Ropp. -Rewrite (Rabsolu_right (sum_f_R0 [i:nat](Rabsolu (An (plus (S n) i))) (minus m (S n)))). -Pose Bn:=[i:nat](An (plus (S n) i)). -Replace [i:nat](Rabsolu (An (plus (S n) i))) with [i:nat](Rabsolu (Bn i)). -Apply Rabsolu_triang_gen. -Unfold Bn; Reflexivity. -Apply Rle_sym1. -Apply cond_pos_sum. -Intro; Apply Rabsolu_pos. -Rewrite b. -Unfold R_dist. -Unfold Rminus; Do 2 Rewrite Rplus_Ropp_r. -Rewrite Rabsolu_R0; Right; Reflexivity. -Rewrite (tech2 An m n); [Idtac | Assumption]. -Rewrite (tech2 [i:nat](Rabsolu (An i)) m n); [Idtac | Assumption]. -Unfold R_dist. -Unfold Rminus. -Do 2 Rewrite Rplus_assoc. -Rewrite (Rplus_sym (sum_f_R0 An m)). -Rewrite (Rplus_sym (sum_f_R0 [i:nat](Rabsolu (An i)) m)). -Do 2 Rewrite Rplus_assoc. -Do 2 Rewrite Rplus_Ropp_l. -Do 2 Rewrite Rplus_Or. -Rewrite (Rabsolu_right (sum_f_R0 [i:nat](Rabsolu (An (plus (S m) i))) (minus n (S m)))). -Pose Bn:=[i:nat](An (plus (S m) i)). -Replace [i:nat](Rabsolu (An (plus (S m) i))) with [i:nat](Rabsolu (Bn i)). -Apply Rabsolu_triang_gen. -Unfold Bn; Reflexivity. -Apply Rle_sym1. -Apply cond_pos_sum. -Intro; Apply Rabsolu_pos. +Lemma cauchy_abs : + forall An:nat -> R, + Cauchy_crit_series (fun i:nat => Rabs (An i)) -> Cauchy_crit_series An. +unfold Cauchy_crit_series in |- *; unfold Cauchy_crit in |- *. +intros. +elim (H eps H0); intros. +exists x. +intros. +cut + (R_dist (sum_f_R0 An n) (sum_f_R0 An m) <= + R_dist (sum_f_R0 (fun i:nat => Rabs (An i)) n) + (sum_f_R0 (fun i:nat => Rabs (An i)) m)). +intro. +apply Rle_lt_trans with + (R_dist (sum_f_R0 (fun i:nat => Rabs (An i)) n) + (sum_f_R0 (fun i:nat => Rabs (An i)) m)). +assumption. +apply H1; assumption. +assert (H4 := lt_eq_lt_dec n m). +elim H4; intro. +elim a; intro. +rewrite (tech2 An n m); [ idtac | assumption ]. +rewrite (tech2 (fun i:nat => Rabs (An i)) n m); [ idtac | assumption ]. +unfold R_dist in |- *. +unfold Rminus in |- *. +do 2 rewrite Ropp_plus_distr. +do 2 rewrite <- Rplus_assoc. +do 2 rewrite Rplus_opp_r. +do 2 rewrite Rplus_0_l. +do 2 rewrite Rabs_Ropp. +rewrite + (Rabs_right (sum_f_R0 (fun i:nat => Rabs (An (S n + i)%nat)) (m - S n))) + . +pose (Bn := fun i:nat => An (S n + i)%nat). +replace (fun i:nat => Rabs (An (S n + i)%nat)) with + (fun i:nat => Rabs (Bn i)). +apply Rabs_triang_gen. +unfold Bn in |- *; reflexivity. +apply Rle_ge. +apply cond_pos_sum. +intro; apply Rabs_pos. +rewrite b. +unfold R_dist in |- *. +unfold Rminus in |- *; do 2 rewrite Rplus_opp_r. +rewrite Rabs_R0; right; reflexivity. +rewrite (tech2 An m n); [ idtac | assumption ]. +rewrite (tech2 (fun i:nat => Rabs (An i)) m n); [ idtac | assumption ]. +unfold R_dist in |- *. +unfold Rminus in |- *. +do 2 rewrite Rplus_assoc. +rewrite (Rplus_comm (sum_f_R0 An m)). +rewrite (Rplus_comm (sum_f_R0 (fun i:nat => Rabs (An i)) m)). +do 2 rewrite Rplus_assoc. +do 2 rewrite Rplus_opp_l. +do 2 rewrite Rplus_0_r. +rewrite + (Rabs_right (sum_f_R0 (fun i:nat => Rabs (An (S m + i)%nat)) (n - S m))) + . +pose (Bn := fun i:nat => An (S m + i)%nat). +replace (fun i:nat => Rabs (An (S m + i)%nat)) with + (fun i:nat => Rabs (Bn i)). +apply Rabs_triang_gen. +unfold Bn in |- *; reflexivity. +apply Rle_ge. +apply cond_pos_sum. +intro; apply Rabs_pos. Qed. (**********) -Lemma cv_cauchy_1 : (An:nat->R) (sigTT R [l:R](Un_cv [N:nat](sum_f_R0 An N) l)) -> (Cauchy_crit_series An). -Intros. -Elim X; Intros. -Unfold Un_cv in p. -Unfold Cauchy_crit_series; Unfold Cauchy_crit. -Intros. -Cut ``0<eps/2``. -Intro. -Elim (p ``eps/2`` H0); Intros. -Exists x0. -Intros. -Apply Rle_lt_trans with ``(R_dist (sum_f_R0 An n) x)+(R_dist (sum_f_R0 An m) x)``. -Unfold R_dist. -Replace ``(sum_f_R0 An n)-(sum_f_R0 An m)`` with ``((sum_f_R0 An n)-x)+ -((sum_f_R0 An m)-x)``; [Idtac | Ring]. -Rewrite <- (Rabsolu_Ropp ``(sum_f_R0 An m)-x``). -Apply Rabsolu_triang. -Apply Rlt_le_trans with ``eps/2+eps/2``. -Apply Rplus_lt. -Apply H1; Assumption. -Apply H1; Assumption. -Right; Symmetry; Apply double_var. -Unfold Rdiv; Apply Rmult_lt_pos; [Assumption | Apply Rlt_Rinv; Sup0]. +Lemma cv_cauchy_1 : + forall An:nat -> R, + sigT (fun l:R => Un_cv (fun N:nat => sum_f_R0 An N) l) -> + Cauchy_crit_series An. +intros. +elim X; intros. +unfold Un_cv in p. +unfold Cauchy_crit_series in |- *; unfold Cauchy_crit in |- *. +intros. +cut (0 < eps / 2). +intro. +elim (p (eps / 2) H0); intros. +exists x0. +intros. +apply Rle_lt_trans with (R_dist (sum_f_R0 An n) x + R_dist (sum_f_R0 An m) x). +unfold R_dist in |- *. +replace (sum_f_R0 An n - sum_f_R0 An m) with + (sum_f_R0 An n - x + - (sum_f_R0 An m - x)); [ idtac | ring ]. +rewrite <- (Rabs_Ropp (sum_f_R0 An m - x)). +apply Rabs_triang. +apply Rlt_le_trans with (eps / 2 + eps / 2). +apply Rplus_lt_compat. +apply H1; assumption. +apply H1; assumption. +right; symmetry in |- *; apply double_var. +unfold Rdiv in |- *; apply Rmult_lt_0_compat; + [ assumption | apply Rinv_0_lt_compat; prove_sup0 ]. Qed. -Lemma cv_cauchy_2 : (An:nat->R) (Cauchy_crit_series An) -> (sigTT R [l:R](Un_cv [N:nat](sum_f_R0 An N) l)). -Intros. -Apply R_complete. -Unfold Cauchy_crit_series in H. -Exact H. +Lemma cv_cauchy_2 : + forall An:nat -> R, + Cauchy_crit_series An -> + sigT (fun l:R => Un_cv (fun N:nat => sum_f_R0 An N) l). +intros. +apply R_complete. +unfold Cauchy_crit_series in H. +exact H. Qed. (**********) -Lemma sum_eq_R0 : (An:nat->R;N:nat) ((n:nat)(le n N)->``(An n)==0``) -> (sum_f_R0 An N)==R0. -Intros; Induction N. -Simpl; Apply H; Apply le_n. -Rewrite tech5; Rewrite HrecN; [Rewrite Rplus_Ol; Apply H; Apply le_n | Intros; Apply H; Apply le_trans with N; [Assumption | Apply le_n_Sn]]. +Lemma sum_eq_R0 : + forall (An:nat -> R) (N:nat), + (forall n:nat, (n <= N)%nat -> An n = 0) -> sum_f_R0 An N = 0. +intros; induction N as [| N HrecN]. +simpl in |- *; apply H; apply le_n. +rewrite tech5; rewrite HrecN; + [ rewrite Rplus_0_l; apply H; apply le_n + | intros; apply H; apply le_trans with N; [ assumption | apply le_n_Sn ] ]. Qed. -Definition SP [fn:nat->R->R;N:nat] : R->R := [x:R](sum_f_R0 [k:nat]``(fn k x)`` N). +Definition SP (fn:nat -> R -> R) (N:nat) (x:R) : R := + sum_f_R0 (fun k:nat => fn k x) N. (**********) -Lemma sum_incr : (An:nat->R;N:nat;l:R) (Un_cv [n:nat](sum_f_R0 An n) l) -> ((n:nat)``0<=(An n)``) -> ``(sum_f_R0 An N)<=l``. -Intros; Case (total_order_T (sum_f_R0 An N) l); Intro. -Elim s; Intro. -Left; Apply a. -Right; Apply b. -Cut (Un_growing [n:nat](sum_f_R0 An n)). -Intro; Pose l1 := (sum_f_R0 An N). -Fold l1 in r. -Unfold Un_cv in H; Cut ``0<l1-l``. -Intro; Elim (H ? H2); Intros. -Pose N0 := (max x N); Cut (ge N0 x). -Intro; Assert H5 := (H3 N0 H4). -Cut ``l1<=(sum_f_R0 An N0)``. -Intro; Unfold R_dist in H5; Rewrite Rabsolu_right in H5. -Cut ``(sum_f_R0 An N0)<l1``. -Intro; Elim (Rlt_antirefl ? (Rlt_le_trans ? ? ? H7 H6)). -Apply Rlt_anti_compatibility with ``-l``. -Do 2 Rewrite (Rplus_sym ``-l``). -Apply H5. -Apply Rle_sym1; Apply Rle_anti_compatibility with l. -Rewrite Rplus_Or; Replace ``l+((sum_f_R0 An N0)-l)`` with (sum_f_R0 An N0); [Idtac | Ring]; Apply Rle_trans with l1. -Left; Apply r. -Apply H6. -Unfold l1; Apply Rle_sym2; Apply (growing_prop [k:nat](sum_f_R0 An k)). -Apply H1. -Unfold ge N0; Apply le_max_r. -Unfold ge N0; Apply le_max_l. -Apply Rlt_anti_compatibility with l; Rewrite Rplus_Or; Replace ``l+(l1-l)`` with l1; [Apply r | Ring]. -Unfold Un_growing; Intro; Simpl; Pattern 1 (sum_f_R0 An n); Rewrite <- Rplus_Or; Apply Rle_compatibility; Apply H0. +Lemma sum_incr : + forall (An:nat -> R) (N:nat) (l:R), + Un_cv (fun n:nat => sum_f_R0 An n) l -> + (forall n:nat, 0 <= An n) -> sum_f_R0 An N <= l. +intros; case (total_order_T (sum_f_R0 An N) l); intro. +elim s; intro. +left; apply a. +right; apply b. +cut (Un_growing (fun n:nat => sum_f_R0 An n)). +intro; pose (l1 := sum_f_R0 An N). +fold l1 in r. +unfold Un_cv in H; cut (0 < l1 - l). +intro; elim (H _ H2); intros. +pose (N0 := max x N); cut (N0 >= x)%nat. +intro; assert (H5 := H3 N0 H4). +cut (l1 <= sum_f_R0 An N0). +intro; unfold R_dist in H5; rewrite Rabs_right in H5. +cut (sum_f_R0 An N0 < l1). +intro; elim (Rlt_irrefl _ (Rlt_le_trans _ _ _ H7 H6)). +apply Rplus_lt_reg_r with (- l). +do 2 rewrite (Rplus_comm (- l)). +apply H5. +apply Rle_ge; apply Rplus_le_reg_l with l. +rewrite Rplus_0_r; replace (l + (sum_f_R0 An N0 - l)) with (sum_f_R0 An N0); + [ idtac | ring ]; apply Rle_trans with l1. +left; apply r. +apply H6. +unfold l1 in |- *; apply Rge_le; + apply (growing_prop (fun k:nat => sum_f_R0 An k)). +apply H1. +unfold ge, N0 in |- *; apply le_max_r. +unfold ge, N0 in |- *; apply le_max_l. +apply Rplus_lt_reg_r with l; rewrite Rplus_0_r; + replace (l + (l1 - l)) with l1; [ apply r | ring ]. +unfold Un_growing in |- *; intro; simpl in |- *; + pattern (sum_f_R0 An n) at 1 in |- *; rewrite <- Rplus_0_r; + apply Rplus_le_compat_l; apply H0. Qed. (**********) -Lemma sum_cv_maj : (An:nat->R;fn:nat->R->R;x,l1,l2:R) (Un_cv [n:nat](SP fn n x) l1) -> (Un_cv [n:nat](sum_f_R0 An n) l2) -> ((n:nat)``(Rabsolu (fn n x))<=(An n)``) -> ``(Rabsolu l1)<=l2``. -Intros; Case (total_order_T (Rabsolu l1) l2); Intro. -Elim s; Intro. -Left; Apply a. -Right; Apply b. -Cut (n0:nat)``(Rabsolu (SP fn n0 x))<=(sum_f_R0 An n0)``. -Intro; Cut ``0<((Rabsolu l1)-l2)/2``. -Intro; Unfold Un_cv in H H0. -Elim (H ? H3); Intros Na H4. -Elim (H0 ? H3); Intros Nb H5. -Pose N := (max Na Nb). -Unfold R_dist in H4 H5. -Cut ``(Rabsolu ((sum_f_R0 An N)-l2))<((Rabsolu l1)-l2)/2``. -Intro; Cut ``(Rabsolu ((Rabsolu l1)-(Rabsolu (SP fn N x))))<((Rabsolu l1)-l2)/2``. -Intro; Cut ``(sum_f_R0 An N)<((Rabsolu l1)+l2)/2``. -Intro; Cut ``((Rabsolu l1)+l2)/2<(Rabsolu (SP fn N x))``. -Intro; Cut ``(sum_f_R0 An N)<(Rabsolu (SP fn N x))``. -Intro; Assert H11 := (H2 N). -Elim (Rlt_antirefl ? (Rle_lt_trans ? ? ? H11 H10)). -Apply Rlt_trans with ``((Rabsolu l1)+l2)/2``; Assumption. -Case (case_Rabsolu ``(Rabsolu l1)-(Rabsolu (SP fn N x))``); Intro. -Apply Rlt_trans with (Rabsolu l1). -Apply Rlt_monotony_contra with ``2``. -Sup0. -Unfold Rdiv; Rewrite (Rmult_sym ``2``); Rewrite Rmult_assoc; Rewrite <- Rinv_l_sym. -Rewrite Rmult_1r; Rewrite double; Apply Rlt_compatibility; Apply r. -DiscrR. -Apply (Rminus_lt ? ? r0). -Rewrite (Rabsolu_right ? r0) in H7. -Apply Rlt_anti_compatibility with ``((Rabsolu l1)-l2)/2-(Rabsolu (SP fn N x))``. -Replace ``((Rabsolu l1)-l2)/2-(Rabsolu (SP fn N x))+((Rabsolu l1)+l2)/2`` with ``(Rabsolu l1)-(Rabsolu (SP fn N x))``. -Unfold Rminus; Rewrite Rplus_assoc; Rewrite Rplus_Ropp_l; Rewrite Rplus_Or; Apply H7. -Unfold Rdiv; Rewrite Rmult_Rplus_distrl; Rewrite <- (Rmult_sym ``/2``); Rewrite Rminus_distr; Repeat Rewrite (Rmult_sym ``/2``); Pattern 1 (Rabsolu l1); Rewrite double_var; Unfold Rdiv; Ring. -Case (case_Rabsolu ``(sum_f_R0 An N)-l2``); Intro. -Apply Rlt_trans with l2. -Apply (Rminus_lt ? ? r0). -Apply Rlt_monotony_contra with ``2``. -Sup0. -Rewrite (double l2); Unfold Rdiv; Rewrite (Rmult_sym ``2``); Rewrite Rmult_assoc; Rewrite <- Rinv_l_sym. -Rewrite Rmult_1r; Rewrite (Rplus_sym (Rabsolu l1)); Apply Rlt_compatibility; Apply r. -DiscrR. -Rewrite (Rabsolu_right ? r0) in H6; Apply Rlt_anti_compatibility with ``-l2``. -Replace ``-l2+((Rabsolu l1)+l2)/2`` with ``((Rabsolu l1)-l2)/2``. -Rewrite Rplus_sym; Apply H6. -Unfold Rdiv; Rewrite <- (Rmult_sym ``/2``); Rewrite Rminus_distr; Rewrite Rmult_Rplus_distrl; Pattern 2 l2; Rewrite double_var; Repeat Rewrite (Rmult_sym ``/2``); Rewrite Ropp_distr1; Unfold Rdiv; Ring. -Apply Rle_lt_trans with ``(Rabsolu ((SP fn N x)-l1))``. -Rewrite <- Rabsolu_Ropp; Rewrite Ropp_distr3; Apply Rabsolu_triang_inv2. -Apply H4; Unfold ge N; Apply le_max_l. -Apply H5; Unfold ge N; Apply le_max_r. -Unfold Rdiv; Apply Rmult_lt_pos. -Apply Rlt_anti_compatibility with l2. -Rewrite Rplus_Or; Replace ``l2+((Rabsolu l1)-l2)`` with (Rabsolu l1); [Apply r | Ring]. -Apply Rlt_Rinv; Sup0. -Intros; Induction n0. -Unfold SP; Simpl; Apply H1. -Unfold SP; Simpl. -Apply Rle_trans with (Rplus (Rabsolu (sum_f_R0 [k:nat](fn k x) n0)) (Rabsolu (fn (S n0) x))). -Apply Rabsolu_triang. -Apply Rle_trans with ``(sum_f_R0 An n0)+(Rabsolu (fn (S n0) x))``. -Do 2 Rewrite <- (Rplus_sym (Rabsolu (fn (S n0) x))). -Apply Rle_compatibility; Apply Hrecn0. -Apply Rle_compatibility; Apply H1. -Qed. +Lemma sum_cv_maj : + forall (An:nat -> R) (fn:nat -> R -> R) (x l1 l2:R), + Un_cv (fun n:nat => SP fn n x) l1 -> + Un_cv (fun n:nat => sum_f_R0 An n) l2 -> + (forall n:nat, Rabs (fn n x) <= An n) -> Rabs l1 <= l2. +intros; case (total_order_T (Rabs l1) l2); intro. +elim s; intro. +left; apply a. +right; apply b. +cut (forall n0:nat, Rabs (SP fn n0 x) <= sum_f_R0 An n0). +intro; cut (0 < (Rabs l1 - l2) / 2). +intro; unfold Un_cv in H, H0. +elim (H _ H3); intros Na H4. +elim (H0 _ H3); intros Nb H5. +pose (N := max Na Nb). +unfold R_dist in H4, H5. +cut (Rabs (sum_f_R0 An N - l2) < (Rabs l1 - l2) / 2). +intro; cut (Rabs (Rabs l1 - Rabs (SP fn N x)) < (Rabs l1 - l2) / 2). +intro; cut (sum_f_R0 An N < (Rabs l1 + l2) / 2). +intro; cut ((Rabs l1 + l2) / 2 < Rabs (SP fn N x)). +intro; cut (sum_f_R0 An N < Rabs (SP fn N x)). +intro; assert (H11 := H2 N). +elim (Rlt_irrefl _ (Rle_lt_trans _ _ _ H11 H10)). +apply Rlt_trans with ((Rabs l1 + l2) / 2); assumption. +case (Rcase_abs (Rabs l1 - Rabs (SP fn N x))); intro. +apply Rlt_trans with (Rabs l1). +apply Rmult_lt_reg_l with 2. +prove_sup0. +unfold Rdiv in |- *; rewrite (Rmult_comm 2); rewrite Rmult_assoc; + rewrite <- Rinv_l_sym. +rewrite Rmult_1_r; rewrite double; apply Rplus_lt_compat_l; apply r. +discrR. +apply (Rminus_lt _ _ r0). +rewrite (Rabs_right _ r0) in H7. +apply Rplus_lt_reg_r with ((Rabs l1 - l2) / 2 - Rabs (SP fn N x)). +replace ((Rabs l1 - l2) / 2 - Rabs (SP fn N x) + (Rabs l1 + l2) / 2) with + (Rabs l1 - Rabs (SP fn N x)). +unfold Rminus in |- *; rewrite Rplus_assoc; rewrite Rplus_opp_l; + rewrite Rplus_0_r; apply H7. +unfold Rdiv in |- *; rewrite Rmult_plus_distr_r; + rewrite <- (Rmult_comm (/ 2)); rewrite Rmult_minus_distr_l; + repeat rewrite (Rmult_comm (/ 2)); pattern (Rabs l1) at 1 in |- *; + rewrite double_var; unfold Rdiv in |- *; ring. +case (Rcase_abs (sum_f_R0 An N - l2)); intro. +apply Rlt_trans with l2. +apply (Rminus_lt _ _ r0). +apply Rmult_lt_reg_l with 2. +prove_sup0. +rewrite (double l2); unfold Rdiv in |- *; rewrite (Rmult_comm 2); + rewrite Rmult_assoc; rewrite <- Rinv_l_sym. +rewrite Rmult_1_r; rewrite (Rplus_comm (Rabs l1)); apply Rplus_lt_compat_l; + apply r. +discrR. +rewrite (Rabs_right _ r0) in H6; apply Rplus_lt_reg_r with (- l2). +replace (- l2 + (Rabs l1 + l2) / 2) with ((Rabs l1 - l2) / 2). +rewrite Rplus_comm; apply H6. +unfold Rdiv in |- *; rewrite <- (Rmult_comm (/ 2)); + rewrite Rmult_minus_distr_l; rewrite Rmult_plus_distr_r; + pattern l2 at 2 in |- *; rewrite double_var; + repeat rewrite (Rmult_comm (/ 2)); rewrite Ropp_plus_distr; + unfold Rdiv in |- *; ring. +apply Rle_lt_trans with (Rabs (SP fn N x - l1)). +rewrite <- Rabs_Ropp; rewrite Ropp_minus_distr'; apply Rabs_triang_inv2. +apply H4; unfold ge, N in |- *; apply le_max_l. +apply H5; unfold ge, N in |- *; apply le_max_r. +unfold Rdiv in |- *; apply Rmult_lt_0_compat. +apply Rplus_lt_reg_r with l2. +rewrite Rplus_0_r; replace (l2 + (Rabs l1 - l2)) with (Rabs l1); + [ apply r | ring ]. +apply Rinv_0_lt_compat; prove_sup0. +intros; induction n0 as [| n0 Hrecn0]. +unfold SP in |- *; simpl in |- *; apply H1. +unfold SP in |- *; simpl in |- *. +apply Rle_trans with + (Rabs (sum_f_R0 (fun k:nat => fn k x) n0) + Rabs (fn (S n0) x)). +apply Rabs_triang. +apply Rle_trans with (sum_f_R0 An n0 + Rabs (fn (S n0) x)). +do 2 rewrite <- (Rplus_comm (Rabs (fn (S n0) x))). +apply Rplus_le_compat_l; apply Hrecn0. +apply Rplus_le_compat_l; apply H1. +Qed.
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