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+(***********************************************************************)
+(*  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*)
+
+
+Require Max.
+Require Raxioms.
+Require DiscrR.
+Require Rbase.
+Require Rseries.
+Require Rtrigo_fun.
+
+Axiom fct_eq : (A:Type)(f1,f2:A->R) ((x:A)(f1 x)==(f2 x)) -> f1 == f2.
+
+Definition SigT := Specif.sigT.
+
+Lemma not_sym : (r1,r2:R) ``r1<>r2`` -> ``r2<>r1``.
+Intros; Red; Intro H0; Rewrite H0 in H; Elim H; Reflexivity.
+Qed.
+
+Lemma Rgt_2_0 : ``0<2``.
+Cut ~(O=(2)); [Intro H0; Generalize (lt_INR_0 (2) (neq_O_lt (2) H0)); Unfold INR; Intro H; Assumption | Discriminate].
+Qed.
+
+Lemma Rgt_3_0 : ``0<3``.
+Cut ~(O=(3)); [Intro H0; Generalize (lt_INR_0 (3) (neq_O_lt (3) H0)); Rewrite INR_eq_INR2; Unfold INR2; Intro H; Assumption | Discriminate].
+Qed.
+
+(*********************)
+(* Lemmes techniques *)
+(*********************)
+
+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.
+Replace (sum_f_R0 An (S N)) with ``(sum_f_R0 An N)+(An (S N))``.
+Apply gt0_plus_gt0_is_gt0.
+Apply HrecN; Intros; Apply H.
+Apply le_S; Assumption.
+Apply H.
+Apply le_n.
+Reflexivity.
+Qed.
+
+(* Relation de Chasles *)
+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.
+Replace (minus (S n) (S n)) with O.
+Simpl.
+Replace (plus n O) with n; [Idtac | Ring].
+Reflexivity.
+Apply minus_n_n.
+Inversion H.
+Right; Reflexivity.
+Left.
+Apply lt_le_trans with (S m).
+Apply lt_n_Sn.
+Assumption.
+Qed.
+
+(* Somme d'une suite géométrique *)
+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.
+Induction N.
+Simpl.
+Field.
+Replace ``1+ -k`` with ``1-k``; [Idtac | Ring].
+Apply Rminus_eq_contra.
+Apply not_sym.
+Assumption.
+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)``; [Idtac | Field; Replace ``1+ -k`` with ``1-k``; [Idtac | Ring]; Apply Rminus_eq_contra; Apply not_sym; Assumption].
+Replace ``(1-(pow k (S N))+(1-k)*(pow k (S N)))`` with ``1-k*(pow k (S N))``; [Idtac | Ring].
+Replace (S (S N)) with (plus (1) (S N)).
+Rewrite pow_add.
+Simpl.
+Rewrite Rmult_1r.
+Reflexivity.
+Ring.
+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.
+Qed.
+
+Lemma tech5 : (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))).
+Replace ``(sum_f_R0 An (S N))`` with ``(sum_f_R0 An N)+(An (S N))``.
+Do 2 Rewrite <- (Rplus_sym (An (S N))).
+Apply Rle_compatibility.
+Apply HrecN.
+Symmetry; Apply tech5.
+Rewrite tech5.
+Rewrite Rmult_Rplus_distr.
+Apply Rle_compatibility.
+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.
+Qed.
+
+Lemma tech8 : (n,i:nat) (le n (plus (S n) i)).
+Intros.
+Induction i.
+Replace (plus (S n) O) with (S n).
+Apply le_n_Sn.
+Ring.
+Replace (plus (S n) (S i)) with (S (plus (S n) i)).
+Apply le_S; Assumption.
+Cut (m:nat)(S m)=(plus m (1)); [Intro | Intro; Ring].
+Rewrite H.
+Rewrite (H n).
+Rewrite (H i).
+Ring.
+Qed.
+
+Lemma tech9 : (Un:nat->R) (Un_growing Un) -> ((m,n:nat)(le m n)->``(Un m)<=(Un n)``).
+Intros.
+Unfold Un_growing in H.
+Induction n.
+Induction m.
+Right; Reflexivity.
+Elim (le_Sn_O ? H0).
+Cut (le m n)\/m=(S n).
+Intro; Elim H1; Intro.
+Apply Rle_trans with (Un n).
+Apply Hrecn; Assumption.
+Apply H.
+Rewrite H2; Right; Reflexivity.
+Inversion H0.
+Right; Reflexivity.
+Left; Assumption.
+Qed.
+
+Lemma tech10 : (Un:nat->R;x:R) (Un_growing Un) -> (is_lub (EUn Un) x) -> (Un_cv Un x).
+Intros.
+Cut (bound (EUn Un)).
+Intro.
+Assert H2 := (Un_cv_crit ? H H1).
+Elim H2; Intros.
+Case (total_order_T x x0); Intro.
+Elim s; Intro.
+Cut (n:nat)``(Un n)<=x``.
+Intro.
+Unfold Un_cv in H3.
+Cut ``0<x0-x``.
+Intro.
+Elim (H3 ``x0-x`` H5); Intros.
+Cut (ge x1 x1).
+Intro.
+Assert H8 := (H6 x1 H7).
+Unfold R_dist in H8.
+Rewrite Rabsolu_left1 in H8.
+Rewrite Ropp_distr2 in H8.
+Unfold Rminus in H8.
+Assert H9 := (Rlt_anti_compatibility ``x0`` ? ? H8).
+Assert H10 := (Ropp_Rlt ? ? H9).
+Assert H11 := (H4 x1).
+Elim (Rlt_antirefl ? (Rlt_le_trans ? ? ? H10 H11)).
+Apply Rle_minus.
+Apply Rle_trans with x.
+Apply H4.
+Left; Assumption.
+Unfold ge; Apply le_n.
+Apply Rgt_minus.
+Assumption.
+Intro.
+Unfold is_lub in H0.
+Unfold is_upper_bound in H0.
+Elim H0; Intros.
+Apply H4.
+Unfold EUn.
+Exists n.
+Reflexivity.
+Rewrite b; Assumption.
+Cut ((n:nat)``(Un n)<=x0``).
+Intro.
+Unfold is_lub in H0.
+Unfold is_upper_bound in H0.
+Elim H0; Intros.
+Cut (y:R)(EUn Un y)->``y<=x0``.
+Intro.
+Assert H8 := (H6 ? H7). 
+Elim (Rlt_antirefl ? (Rle_lt_trans ? ? ? H8 r)).
+Unfold EUn.
+Intros.
+Elim H7; Intros.
+Rewrite H8; Apply H4.
+Intro.
+Case (total_order_Rle (Un n) x0); Intro.
+Assumption.
+Cut (n0:nat)(le n n0) -> ``x0<(Un n0)``. 
+Intro.
+Unfold Un_cv in H3.
+Cut ``0<(Un n)-x0``.
+Intro.
+Elim (H3 ``(Un n)-x0`` H5); Intros.
+Cut (ge (max n x1) x1).
+Intro.
+Assert H8 := (H6 (max n x1) H7).
+Unfold R_dist in H8.
+Rewrite Rabsolu_right in H8.
+Unfold Rminus in H8; Do 2 Rewrite <- (Rplus_sym ``-x0``) in H8.
+Assert H9 := (Rlt_anti_compatibility ? ? ? H8).
+Cut ``(Un n)<=(Un (max n x1))``.
+Intro.
+Elim (Rlt_antirefl ? (Rle_lt_trans ? ? ? H10 H9)).
+Apply tech9.
+Assumption.
+Apply le_max_l.
+Apply Rge_trans with ``(Un n)-x0``.
+Unfold Rminus; Apply Rle_sym1.
+Do 2 Rewrite <- (Rplus_sym ``-x0``).
+Apply Rle_compatibility.
+Apply tech9.
+Assumption.
+Apply le_max_l.
+Left; Assumption.
+Unfold ge; Apply le_max_r.
+Apply Rlt_anti_compatibility with x0.
+Rewrite Rplus_Or.
+Unfold Rminus; Rewrite (Rplus_sym x0).
+Rewrite Rplus_assoc; Rewrite Rplus_Ropp_l; Rewrite Rplus_Or.
+Apply H4.
+Apply le_n.
+Intros.
+Apply Rlt_le_trans with (Un n).
+Case (total_order_Rlt_Rle x0 (Un n)); Intro.
+Assumption.
+Elim n0; Assumption.
+Apply tech9; Assumption.
+Unfold bound.
+Exists x.
+Unfold is_lub in H0.
+Elim H0; Intros; 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.
+Replace (sum_f_R0 An (S N)) with ``(sum_f_R0 An N)+(An (S N))``; [Idtac | Reflexivity].
+Replace (sum_f_R0 Bn (S N)) with ``(sum_f_R0 Bn N)+(Bn (S N))``; [Idtac | Reflexivity].
+Replace (sum_f_R0 Cn (S N)) with ``(sum_f_R0 Cn N)+(Cn (S N))``; [Idtac | Reflexivity].
+Rewrite HrecN.
+Unfold Rminus.
+Repeat Rewrite Rplus_assoc.
+Apply Rplus_plus_r.
+Rewrite Ropp_distr1.
+Rewrite <- Rplus_assoc.
+Rewrite <- (Rplus_sym ``-(sum_f_R0 Cn N)``).
+Rewrite Rplus_assoc.
+Apply Rplus_plus_r.
+Unfold Rminus in H.
+Apply H.
+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.
+Qed. 
+
+Lemma tech13 : (An:nat->R;k:R) ``0<=k<1`` -> (Un_cv [n:nat](Rabsolu ``(An (S n))/(An n)``) k) -> (EXT k0 : R | ``k<k0<1`` /\ (EX N:nat | (n:nat) (le N n)->``(Rabsolu ((An (S n))/(An n)))<k0``)).
+Intros.
+Exists ``k+(1-k)/2``.
+Split.
+Split.
+Pattern 1 k; Rewrite <- Rplus_Or.
+Apply Rlt_compatibility.
+Unfold Rdiv; Apply Rmult_lt_pos.
+Apply Rlt_anti_compatibility with k; Rewrite Rplus_Or.
+Replace ``k+(1-k)`` with R1; [Elim H; Intros; Assumption | Ring].
+Apply Rlt_Rinv; Apply Rgt_2_0.
+Apply Rlt_monotony_contra with ``2``.
+Apply Rgt_2_0.
+Unfold Rdiv.
+Rewrite Rmult_1r.
+Rewrite Rmult_Rplus_distr.
+Pattern 1 ``2``; Rewrite Rmult_sym.
+Rewrite Rmult_assoc.
+Rewrite <- Rinv_l_sym; [Idtac | DiscrR].
+Rewrite Rmult_1r.
+Replace ``2*k+(1-k)`` with ``1+k``; [Idtac | Ring].
+Elim H; Intros.
+Apply Rlt_compatibility; Assumption.
+Unfold Un_cv in H0.
+Cut ``0<(1-k)/2``.
+Intro.
+Elim (H0 ``(1-k)/2`` H1); Intros.
+Exists x.
+Intros.
+Assert H4 := (H2 n H3).
+Unfold R_dist in H4.
+Rewrite <- Rabsolu_Rabsolu.
+Replace ``(Rabsolu ((An (S n))/(An n)))`` with ``((Rabsolu ((An (S n))/(An n)))-k)+k``; [Idtac | Ring].
+Apply Rle_lt_trans with ``(Rabsolu ((Rabsolu ((An (S n))/(An n)))-k))+(Rabsolu k)``.
+Apply Rabsolu_triang.
+Rewrite (Rabsolu_right k).
+Apply Rlt_anti_compatibility with ``-k``.
+Rewrite <- (Rplus_sym k).
+Repeat Rewrite <- Rplus_assoc.
+Rewrite Rplus_Ropp_l.
+Repeat Rewrite Rplus_Ol.
+Apply H4.
+Apply Rle_sym1.
+Elim H; Intros; Assumption.
+Unfold Rdiv; Apply Rmult_lt_pos.
+Apply Rlt_anti_compatibility with k.
+Rewrite Rplus_Or.
+Elim H; Intros.
+Replace ``k+(1-k)`` with R1; [Assumption | Ring].
+Apply Rlt_Rinv; Apply Rgt_2_0.
+Qed.
+
+
+(*************************************************)
+(* Différentes versions du critère de D'Alembert *)
+(*************************************************)
+
+Lemma Alembert_positive :  (An:nat->R) ((n:nat)``0<(An n)``) -> (Un_cv [n:nat](Rabsolu ``(An (S n))/(An n)``) R0) -> (SigT R [l:R](Un_cv [N:nat](sum_f_R0 An N) l)).
+Intros An H H0.
+Cut (sigTT R [l:R](is_lub (EUn [N:nat](sum_f_R0 An N)) l)) -> (SigT R [l:R](Un_cv [N:nat](sum_f_R0 An N) l)).
+Intro.
+Apply X.
+Apply complet.
+2:Exists (sum_f_R0 An O).
+2:Unfold EUn.
+2:Exists O.
+2:Reflexivity.
+Unfold Un_cv in H0.
+Unfold bound.
+Cut ``0</2``; [Intro | Apply Rlt_Rinv; Apply Rgt_2_0].
+Elim (H0 ``/2`` H1); Intros.
+Exists ``(sum_f_R0 An x)+2*(An (S x))``.
+Unfold is_upper_bound.
+Intros.
+Unfold EUn in H3.
+Elim H3; Intros.
+Rewrite H4.
+Assert H5 := (lt_eq_lt_dec x1 x).
+Elim H5; Intros.
+Elim a; Intro.
+Replace (sum_f_R0 An x) with (Rplus (sum_f_R0 An x1) (sum_f_R0 [i:nat](An (plus (S x1) i)) (minus x (S x1)))).
+Pattern 1 (sum_f_R0 An x1); Rewrite <- Rplus_Or.
+Rewrite Rplus_assoc.
+Apply Rle_compatibility.
+Left; Apply gt0_plus_gt0_is_gt0.
+Apply tech1.
+Intros.
+Apply H.
+Apply Rmult_lt_pos.
+Apply Rgt_2_0.
+Apply H.
+Symmetry; Apply tech2; Assumption.
+Rewrite b.
+Pattern 1 (sum_f_R0 An x); Rewrite <- Rplus_Or.
+Apply Rle_compatibility.
+Left; Apply Rmult_lt_pos.
+Apply Rgt_2_0.
+Apply H.
+Replace (sum_f_R0 An x1) with (Rplus (sum_f_R0 An x) (sum_f_R0 [i:nat](An (plus (S x) i)) (minus x1 (S x)))).
+Apply Rle_compatibility.
+2:Symmetry.
+2:Apply tech2.
+2:Assumption.
+Cut (Rle (sum_f_R0 [i:nat](An (plus (S x) i)) (minus x1 (S x))) (Rmult (An (S x)) (sum_f_R0 [i:nat](pow ``/2`` i) (minus x1 (S x))))).
+Intro.
+Apply Rle_trans with (Rmult (An (S x)) (sum_f_R0 [i:nat](pow ``/2`` i) (minus x1 (S x)))).
+Assumption.
+Rewrite <- (Rmult_sym (An (S x))).
+Apply Rle_monotony.
+Left; Apply H.
+Rewrite tech3.
+Replace ``1-/2`` with ``/2``.
+Unfold Rdiv.
+Rewrite Rinv_Rinv.
+Pattern 3 ``2``; Rewrite <- Rmult_1r.
+Rewrite <- (Rmult_sym ``2``).
+Apply Rle_monotony.
+Left; Apply Rgt_2_0.
+Left; Apply Rlt_anti_compatibility with ``(pow (/2) (S (minus x1 (S x))))``.
+Replace ``(pow (/2) (S (minus x1 (S x))))+(1-
+   (pow (/2) (S (minus x1 (S x)))))`` with R1; [Idtac | Ring].
+Rewrite <- (Rplus_sym ``1``).
+Pattern 1 R1; Rewrite <- Rplus_Or.
+Apply Rlt_compatibility.
+Apply pow_lt.
+Apply Rlt_Rinv; Apply Rgt_2_0.
+DiscrR.
+Field.
+DiscrR.
+Pattern 3 R1; Replace R1 with ``/1``.
+2:Apply Rinv_R1.
+Apply tech7; DiscrR.
+Replace (An (S x)) with (An (plus (S x) O)).
+Apply (tech6 [i:nat](An (plus (S x) i)) ``/2``).
+Left; Apply Rlt_Rinv; Apply Rgt_2_0.
+2:Replace (plus (S x) O) with (S x); [Reflexivity | Ring].
+Intro.
+Cut (n:nat)(ge n x)->``(An (S n))</2*(An n)``.
+Intro.
+Replace (plus (S x) (S i)) with (S (plus (S x) i)).
+Apply H6.
+Unfold ge.
+Apply tech8.
+Cut (m:nat)(S m)=(plus m (1)); [Intro | Intro; Ring].
+Rewrite H7.
+Rewrite (H7 x).
+Rewrite (H7 i).
+Ring.
+Intros.
+Unfold R_dist in H2.
+Apply Rlt_monotony_contra with ``/(An n)``.
+Apply Rlt_Rinv; Apply H.
+Do 2 Rewrite (Rmult_sym ``/(An n)``).
+Rewrite Rmult_assoc.
+Rewrite <- Rinv_r_sym.
+Rewrite Rmult_1r.
+Replace ``(An (S n))*/(An n)`` with ``(Rabsolu ((Rabsolu ((An (S n))/(An n)))-0))``.
+Apply H2; Assumption.
+Unfold Rminus; Rewrite Ropp_O; Rewrite Rplus_Or.
+Rewrite Rabsolu_Rabsolu.
+Rewrite Rabsolu_right.
+Unfold Rdiv; Reflexivity.
+Left; Unfold Rdiv; Change ``0<(An (S n))*/(An n)``; Apply Rmult_lt_pos.
+Apply H.
+Apply Rlt_Rinv; Apply H.
+Red; Intro.
+Assert H8 := (H n).
+Rewrite H7 in H8; Elim (Rlt_antirefl ? H8).
+Intro.
+Elim X; Intros.
+Apply Specif.existT with x.
+Apply tech10.
+2:Assumption.
+Unfold Un_growing.
+Intro.
+Rewrite tech5.
+Pattern 1 (sum_f_R0 An n); Rewrite <- Rplus_Or.
+Apply Rle_compatibility.
+Left; Apply H.
+Qed.
+
+Lemma Alembert_general:(An:nat->R) ((n:nat)``(An n)<>0``) -> (Un_cv [n:nat](Rabsolu ``(An (S n))/(An n)``) R0) -> (SigT R  [l:R](Un_cv [N:nat](sum_f_R0 An N) l)).
+Intros.
+Pose Vn := [i:nat]``(2*(Rabsolu (An i))+(An i))/2``.
+Pose Wn := [i:nat]``(2*(Rabsolu (An i))-(An i))/2``.
+Cut (n:nat)``0<(Vn n)``.
+Intro.
+Cut (n:nat)``0<(Wn n)``.
+Intro.
+Cut (Un_cv [n:nat](Rabsolu ``(Vn (S n))/(Vn n)``) ``0``).
+Intro.
+Cut (Un_cv [n:nat](Rabsolu ``(Wn (S n))/(Wn n)``) ``0``).
+Intro.
+Assert H5 := (Alembert_positive Vn H1 H3).
+Assert H6 := (Alembert_positive Wn H2 H4).
+Elim H5; Intros.
+Elim H6; Intros.
+Apply Specif.existT with ``x-x0``.
+Unfold Un_cv.
+Unfold Un_cv in p.
+Unfold Un_cv in p0.
+Intros.
+Cut ``0<eps/2``.
+Intro.
+Elim (p ``eps/2`` H8); Clear p; Intros.
+Elim (p0 ``eps/2`` H8); Clear p0; Intros.
+Pose N := (max x1 x2).
+Exists N.
+Intros.
+Replace (sum_f_R0 An n) with (Rminus (sum_f_R0 Vn n) (sum_f_R0 Wn n)).
+Unfold R_dist.
+Replace (Rminus (Rminus (sum_f_R0 Vn n) (sum_f_R0 Wn n)) (Rminus x x0)) with (Rplus (Rminus (sum_f_R0 Vn n) x) (Ropp (Rminus (sum_f_R0 Wn n) x0))); [Idtac | Ring].
+Apply Rle_lt_trans with (Rplus (Rabsolu (Rminus (sum_f_R0 Vn n) x)) (Rabsolu (Ropp (Rminus (sum_f_R0 Wn n) x0)))).
+Apply Rabsolu_triang.
+Rewrite Rabsolu_Ropp.
+Apply Rlt_le_trans with ``eps/2+eps/2``.
+Apply Rplus_lt.
+Unfold R_dist in H9.
+Apply H9.
+Unfold ge; Apply le_trans with N.
+Unfold N; Apply le_max_l.
+Assumption.
+Unfold R_dist in H10.
+Apply H10.
+Unfold ge; Apply le_trans with N.
+Unfold N; Apply le_max_r.
+Assumption.
+Right; Symmetry; Apply double_var.
+Symmetry; Apply tech11.
+Intro.
+Unfold Vn Wn.
+Field.
+DiscrR.
+Unfold Rdiv; Apply Rmult_lt_pos; [Assumption | Apply Rlt_Rinv; Apply Rgt_2_0].
+Cut (n:nat)``/2*(Rabsolu (An n))<=(Wn n)<=(3*/2)*(Rabsolu (An n))``.
+Intro.
+Cut (n:nat)``/(Wn n)<=2*/(Rabsolu (An n))``.
+Intro.
+Cut (n:nat)``(Wn (S n))/(Wn n)<=3*(Rabsolu (An (S n))/(An n))``.
+Intro.
+Unfold Un_cv.
+Intros.
+Unfold Un_cv in H0.
+Cut ``0<eps/3``.
+Intro.
+Elim (H0 ``eps/3`` H8); Intros.
+Exists x.
+Intros.
+Assert H11 := (H9 n H10).
+Unfold R_dist.
+Unfold Rminus; Rewrite Ropp_O; Rewrite Rplus_Or; Rewrite Rabsolu_Rabsolu.
+Unfold R_dist in H11; Unfold Rminus in H11; Rewrite Ropp_O in H11; Rewrite Rplus_Or in H11; Rewrite Rabsolu_Rabsolu in H11.
+Rewrite Rabsolu_right.
+Apply Rle_lt_trans with ``3*(Rabsolu ((An (S n))/(An n)))``.
+Apply H6.
+Apply Rlt_monotony_contra with ``/3``.
+Apply Rlt_Rinv; Apply Rgt_3_0.
+Rewrite <- Rmult_assoc.
+Rewrite <- Rinv_l_sym; [Idtac | DiscrR].
+Rewrite Rmult_1l.
+Rewrite <- (Rmult_sym eps).
+Unfold Rdiv in H11; Exact H11.
+Left; Change ``0<(Wn (S n))/(Wn n)``; Unfold Rdiv; Apply Rmult_lt_pos.
+Apply H2.
+Apply Rlt_Rinv; Apply H2.
+Unfold Rdiv; Apply Rmult_lt_pos; [Assumption | Apply Rlt_Rinv; Apply Rgt_3_0].
+Intro.
+Unfold Rdiv.
+Rewrite Rabsolu_mult.
+Rewrite <- Rmult_assoc.
+Replace ``3`` with ``2*(3*/2)``; [Idtac | Field; DiscrR].
+Apply Rle_trans with ``(Wn (S n))*2*/(Rabsolu (An n))``.
+Rewrite Rmult_assoc.
+Apply Rle_monotony.
+Left; Apply H2.
+Apply H5.
+Rewrite Rabsolu_Rinv.
+Replace ``(Wn (S n))*2*/(Rabsolu (An n))`` with ``(2*/(Rabsolu (An n)))*(Wn (S n))``; [Idtac | Ring].
+Replace ``2*(3*/2)*(Rabsolu (An (S n)))*/(Rabsolu (An n))`` with ``(2*/(Rabsolu (An n)))*((3*/2)*(Rabsolu (An (S n))))``; [Idtac | Ring].
+Apply Rle_monotony.
+Left; Apply Rmult_lt_pos.
+Apply Rgt_2_0.
+Apply Rlt_Rinv; Apply Rabsolu_pos_lt; Apply H.
+Elim (H4 (S n)); Intros; Assumption.
+Apply H.
+Intro.
+Apply Rle_monotony_contra with (Wn n).
+Apply H2.
+Rewrite <- Rinv_r_sym.
+Apply Rle_monotony_contra with (Rabsolu (An n)).
+Apply Rabsolu_pos_lt; Apply H.
+Rewrite Rmult_1r.
+Replace ``(Rabsolu (An n))*((Wn n)*(2*/(Rabsolu (An n))))`` with ``2*(Wn n)*((Rabsolu (An n))*/(Rabsolu (An n)))``; [Idtac | Ring].
+Rewrite <- Rinv_r_sym.
+Rewrite Rmult_1r.
+Apply Rle_monotony_contra with ``/2``.
+Apply Rlt_Rinv; Apply Rgt_2_0.
+Rewrite <- Rmult_assoc.
+Rewrite <- Rinv_l_sym.
+Rewrite Rmult_1l; Elim (H4 n); Intros; Assumption.
+DiscrR.
+Apply Rabsolu_no_R0; Apply H.
+Red; Intro; Assert H6 := (H2 n); Rewrite H5 in H6; Elim (Rlt_antirefl ? H6).
+Intro.
+Split.
+Unfold Wn.
+Unfold Rdiv.
+Rewrite <- (Rmult_sym ``/2``).
+Apply Rle_monotony.
+Left; Apply Rlt_Rinv; Apply Rgt_2_0.
+Pattern 1 (Rabsolu (An n)); Rewrite <- Rplus_Or.
+Rewrite double.
+Unfold Rminus.
+Rewrite Rplus_assoc.
+Apply Rle_compatibility.
+Apply Rle_anti_compatibility with (An n).
+Rewrite Rplus_Or.
+Rewrite (Rplus_sym (An n)).
+Rewrite Rplus_assoc; Rewrite Rplus_Ropp_l; Rewrite Rplus_Or.
+Apply Rle_Rabsolu.
+Unfold Wn.
+Unfold Rdiv.
+Repeat Rewrite <- (Rmult_sym ``/2``).
+Repeat Rewrite Rmult_assoc.
+Apply Rle_monotony.
+Left; Apply Rlt_Rinv; Apply Rgt_2_0.
+Unfold Rminus.
+Rewrite double.
+Replace ``3*(Rabsolu (An n))`` with ``(Rabsolu (An n))+(Rabsolu (An n))+(Rabsolu (An n))``; [Idtac | Ring].
+Repeat Rewrite Rplus_assoc.
+Repeat Apply Rle_compatibility.
+Rewrite <- Rabsolu_Ropp.
+Apply Rle_Rabsolu.
+Cut (n:nat)``/2*(Rabsolu (An n))<=(Vn n)<=(3*/2)*(Rabsolu (An n))``.
+Intro.
+Cut (n:nat)``/(Vn n)<=2*/(Rabsolu (An n))``.
+Intro.
+Cut (n:nat)``(Vn (S n))/(Vn n)<=3*(Rabsolu (An (S n))/(An n))``.
+Intro.
+Unfold Un_cv.
+Intros.
+Unfold Un_cv in H1.
+Cut ``0<eps/3``.
+Intro.
+Elim (H0 ``eps/3`` H7); Intros.
+Exists x.
+Intros.
+Assert H10 := (H8 n H9).
+Unfold R_dist.
+Unfold Rminus; Rewrite Ropp_O; Rewrite Rplus_Or; Rewrite Rabsolu_Rabsolu.
+Unfold R_dist in H10; Unfold Rminus in H10; Rewrite Ropp_O in H10; Rewrite Rplus_Or in H10; Rewrite Rabsolu_Rabsolu in H10.
+Rewrite Rabsolu_right.
+Apply Rle_lt_trans with ``3*(Rabsolu ((An (S n))/(An n)))``.
+Apply H5.
+Apply Rlt_monotony_contra with ``/3``.
+Apply Rlt_Rinv; Apply Rgt_3_0.
+Rewrite <- Rmult_assoc.
+Rewrite <- Rinv_l_sym; [Idtac | DiscrR].
+Rewrite Rmult_1l.
+Rewrite <- (Rmult_sym eps).
+Unfold Rdiv in H10; Exact H10.
+Left; Change ``0<(Vn (S n))/(Vn n)``; Unfold Rdiv; Apply Rmult_lt_pos.
+Apply H1.
+Apply Rlt_Rinv; Apply H1.
+Unfold Rdiv; Apply Rmult_lt_pos; [Assumption | Apply Rlt_Rinv; Apply Rgt_3_0].
+Intro.
+Unfold Rdiv.
+Rewrite Rabsolu_mult.
+Rewrite <- Rmult_assoc.
+Replace ``3`` with ``2*(3*/2)``; [Idtac | Field; DiscrR].
+Apply Rle_trans with ``(Vn (S n))*2*/(Rabsolu (An n))``.
+Rewrite Rmult_assoc.
+Apply Rle_monotony.
+Left; Apply H1.
+Apply H4.
+Rewrite Rabsolu_Rinv.
+Replace ``(Vn (S n))*2*/(Rabsolu (An n))`` with ``(2*/(Rabsolu (An n)))*(Vn (S n))``; [Idtac | Ring].
+Replace ``2*(3*/2)*(Rabsolu (An (S n)))*/(Rabsolu (An n))`` with ``(2*/(Rabsolu (An n)))*((3*/2)*(Rabsolu (An (S n))))``; [Idtac | Ring].
+Apply Rle_monotony.
+Left; Apply Rmult_lt_pos.
+Apply Rgt_2_0.
+Apply Rlt_Rinv; Apply Rabsolu_pos_lt; Apply H.
+Elim (H3 (S n)); Intros; Assumption.
+Apply H.
+Intro.
+Apply Rle_monotony_contra with (Vn n).
+Apply H1.
+Rewrite <- Rinv_r_sym.
+Apply Rle_monotony_contra with (Rabsolu (An n)).
+Apply Rabsolu_pos_lt; Apply H.
+Rewrite Rmult_1r.
+Replace ``(Rabsolu (An n))*((Vn n)*(2*/(Rabsolu (An n))))`` with ``2*(Vn n)*((Rabsolu (An n))*/(Rabsolu (An n)))``; [Idtac | Ring].
+Rewrite <- Rinv_r_sym.
+Rewrite Rmult_1r.
+Apply Rle_monotony_contra with ``/2``.
+Apply Rlt_Rinv; Apply Rgt_2_0.
+Rewrite <- Rmult_assoc.
+Rewrite <- Rinv_l_sym.
+Rewrite Rmult_1l; Elim (H3 n); Intros; Assumption.
+DiscrR.
+Apply Rabsolu_no_R0; Apply H.
+Red; Intro; Assert H5 := (H1 n); Rewrite H4 in H5; Elim (Rlt_antirefl ? H5).
+Intro.
+Split.
+Unfold Vn.
+Unfold Rdiv.
+Rewrite <- (Rmult_sym ``/2``).
+Apply Rle_monotony.
+Left; Apply Rlt_Rinv; Apply Rgt_2_0.
+Pattern 1 (Rabsolu (An n)); Rewrite <- Rplus_Or.
+Rewrite double.
+Rewrite Rplus_assoc.
+Apply Rle_compatibility.
+Apply Rle_anti_compatibility with ``-(An n)``.
+Rewrite Rplus_Or.
+Rewrite <- (Rplus_sym (An n)).
+Rewrite <- Rplus_assoc; Rewrite Rplus_Ropp_l; Rewrite Rplus_Ol.
+Rewrite <- Rabsolu_Ropp.
+Apply Rle_Rabsolu.
+Unfold Vn.
+Unfold Rdiv.
+Repeat Rewrite <- (Rmult_sym ``/2``).
+Repeat Rewrite Rmult_assoc.
+Apply Rle_monotony.
+Left; Apply Rlt_Rinv; Apply Rgt_2_0.
+Unfold Rminus.
+Rewrite double.
+Replace ``3*(Rabsolu (An n))`` with ``(Rabsolu (An n))+(Rabsolu (An n))+(Rabsolu (An n))``; [Idtac | Ring].
+Repeat Rewrite Rplus_assoc.
+Repeat Apply Rle_compatibility.
+Apply Rle_Rabsolu.
+Intro.
+Unfold Wn.
+Unfold Rdiv.
+Rewrite <- (Rmult_Or ``/2``).
+Rewrite <- (Rmult_sym ``/2``).
+Apply Rlt_monotony.
+Apply Rlt_Rinv; Apply Rgt_2_0.
+Apply Rlt_anti_compatibility with (An n).
+Rewrite Rplus_Or.
+Unfold Rminus.
+Rewrite (Rplus_sym (An n)).
+Rewrite Rplus_assoc.
+Rewrite Rplus_Ropp_l; Rewrite Rplus_Or.
+Apply Rle_lt_trans with (Rabsolu (An n)).
+Apply Rle_Rabsolu.
+Rewrite double.
+Pattern 1 (Rabsolu (An n)); Rewrite <- Rplus_Or.
+Apply Rlt_compatibility.
+Apply Rabsolu_pos_lt; Apply H.
+Intro.
+Unfold Vn.
+Unfold Rdiv.
+Rewrite <- (Rmult_Or ``/2``).
+Rewrite <- (Rmult_sym ``/2``).
+Apply Rlt_monotony.
+Apply Rlt_Rinv; Apply Rgt_2_0.
+Apply Rlt_anti_compatibility with ``-(An n)``.
+Rewrite Rplus_Or.
+Unfold Rminus.
+Rewrite (Rplus_sym ``-(An n)``).
+Rewrite Rplus_assoc.
+Rewrite Rplus_Ropp_r; Rewrite Rplus_Or.
+Apply Rle_lt_trans with (Rabsolu (An n)).
+Rewrite <- Rabsolu_Ropp.
+Apply Rle_Rabsolu.
+Rewrite double.
+Pattern 1 (Rabsolu (An n)); Rewrite <- Rplus_Or.
+Apply Rlt_compatibility.
+Apply Rabsolu_pos_lt; Apply H.
+Qed.
+
+Lemma Alembert_step1 : (An:nat->R;x:R) ``x<>0`` -> ((n:nat)``(An n)<>0``) -> (Un_cv [n:nat](Rabsolu ``(An (S n))/(An n)``) ``0``) -> (SigT R [l:R](Pser An x l)).
+Intros.
+Pose Bn := [i:nat]``(An i)*(pow x i)``.
+Cut (n:nat)``(Bn n)<>0``.
+Intro.
+Cut (Un_cv [n:nat](Rabsolu ``(Bn (S n))/(Bn n)``) ``0``).
+Intro.
+Assert H4 := (Alembert_general Bn H2 H3).
+Elim H4; Intros.
+Apply Specif.existT with x0.
+Unfold Bn in p.
+Apply tech12. 
+Assumption.
+Unfold Un_cv.
+Intros.
+Unfold Un_cv in H1.
+Cut ``0<eps/(Rabsolu x)``.
+Intro.
+Elim (H1 ``eps/(Rabsolu x)`` H4); Intros.
+Exists x0.
+Intros.
+Unfold R_dist.
+Unfold Rminus; Rewrite Ropp_O; Rewrite Rplus_Or; Rewrite Rabsolu_Rabsolu.
+Unfold Bn.
+Replace ``((An (S n))*(pow x (S n)))/((An n)*(pow x n))`` with ``(An (S n))/(An n)*x``.
+Rewrite Rabsolu_mult.
+Apply Rlt_monotony_contra with ``/(Rabsolu x)``.
+Apply Rlt_Rinv; Apply Rabsolu_pos_lt; Assumption.
+Rewrite <- (Rmult_sym (Rabsolu x)).
+Rewrite <- Rmult_assoc.
+Rewrite <- Rinv_l_sym.
+Rewrite Rmult_1l.
+Rewrite <- (Rmult_sym eps).
+Unfold Rdiv in H5.
+Replace ``(Rabsolu ((An (S n))/(An n)))`` with ``(R_dist (Rabsolu ((An (S n))*/(An n))) 0)``.
+Apply H5; Assumption.
+Unfold R_dist.
+Unfold Rminus; Rewrite Ropp_O; Rewrite Rplus_Or; Rewrite Rabsolu_Rabsolu.
+Unfold Rdiv; Reflexivity.
+Apply Rabsolu_no_R0; Assumption.
+Replace (S n) with (plus n (1)); [Idtac | Ring].
+Rewrite pow_add.
+Unfold Rdiv.
+Rewrite Rinv_Rmult.
+Replace ``(An (plus n (S O)))*((pow x n)*(pow x (S O)))*(/(An n)*/(pow x n))`` with ``(An (plus n (S O)))*(pow x (S O))*/(An n)*((pow x n)*/(pow x n))``; [Idtac | Ring].
+Rewrite <- Rinv_r_sym.
+Simpl.
+Ring.
+Apply pow_nonzero; Assumption.
+Apply H0.
+Apply pow_nonzero; Assumption.
+Unfold Rdiv; Apply Rmult_lt_pos.
+Assumption.
+Apply Rlt_Rinv; Apply Rabsolu_pos_lt; Assumption.
+Intro.
+Unfold Bn.
+Apply prod_neq_R0.
+Apply H0.
+Apply pow_nonzero; Assumption.
+Qed.
+
+Lemma Alembert_step2 : (An:nat->R;x:R) ``x==0`` -> (SigT R [l:R](Pser An x l)).
+Intros.
+Apply Specif.existT with (An O).
+Unfold Pser.
+Unfold infinit_sum.
+Intros.
+Exists O.
+Intros.
+Replace (sum_f_R0 [n0:nat]``(An n0)*(pow x n0)`` n) with (An O).
+Unfold R_dist; Unfold Rminus; Rewrite Rplus_Ropp_r; Rewrite Rabsolu_R0; Assumption.
+Induction n.
+Simpl.
+Ring.
+Rewrite tech5.
+Rewrite Hrecn.
+Rewrite H.
+Simpl.
+Ring.
+Unfold ge; Apply le_O_n.
+Qed.
+
+(* Un critère utile de convergence des séries entières *)
+Theorem Alembert : (An:nat->R;x:R) ((n:nat)``(An n)<>0``) -> (Un_cv [n:nat](Rabsolu ``(An (S n))/(An n)``) ``0``) -> (SigT R [l:R](Pser An x l)).
+Intros.
+Case (total_order_T x R0); Intro.
+Elim s; Intro.
+Cut ``x<>0``.
+Intro.
+Apply Alembert_step1; Assumption.
+Red; Intro; Rewrite H1 in a; Elim (Rlt_antirefl ? a).
+Apply Alembert_step2; Assumption.
+Cut ``x<>0``.
+Intro.
+Apply Alembert_step1; Assumption.
+Red; Intro; Rewrite H1 in r; Elim (Rlt_antirefl ? r).
+Qed.
+
+(* Le "vrai" critère de D'Alembert pour les séries à TG positif *)
+Lemma Alembert_strong_positive : (An:nat->R;k:R) ``0<=k<1`` -> ((n:nat)``0<(An n)``) -> (Un_cv [n:nat](Rabsolu ``(An (S n))/(An n)``) k) -> (SigT R [l:R](Un_cv [N:nat](sum_f_R0 An N) l)).
+Intros An k Hyp H H0.
+Cut (sigTT R [l:R](is_lub (EUn [N:nat](sum_f_R0 An N)) l)) -> (SigT R [l:R](Un_cv [N:nat](sum_f_R0 An N) l)).
+Intro.
+Apply X.
+Apply complet.
+2:Exists (sum_f_R0 An O).
+2:Unfold EUn.
+2:Exists O.
+2:Reflexivity.
+Assert H1 := (tech13 ? ? Hyp H0).
+Elim H1; Intros.
+Elim H2; Intros.
+Elim H4; Intros.
+Unfold bound.
+Exists ``(sum_f_R0 An x0)+/(1-x)*(An (S x0))``.
+Unfold is_upper_bound.
+Intros.
+Unfold EUn in H6.
+Elim H6; Intros.
+Rewrite H7.
+Assert H8 := (lt_eq_lt_dec x2 x0).
+Elim H8; Intros.
+Elim a; Intro.
+Replace (sum_f_R0 An x0) with (Rplus (sum_f_R0 An x2) (sum_f_R0 [i:nat](An (plus (S x2) i)) (minus x0 (S x2)))).
+Pattern 1 (sum_f_R0 An x2); Rewrite <- Rplus_Or.
+Rewrite Rplus_assoc.
+Apply Rle_compatibility.
+Left; Apply gt0_plus_gt0_is_gt0.
+Apply tech1.
+Intros.
+Apply H.
+Apply Rmult_lt_pos.
+Apply Rlt_Rinv.
+Apply Rlt_anti_compatibility with x.
+Rewrite Rplus_Or.
+Replace ``x+(1-x)`` with R1; [Elim H3; Intros; Assumption | Ring].
+Apply H.
+Symmetry; Apply tech2; Assumption.
+Rewrite b.
+Pattern 1 (sum_f_R0 An x0); Rewrite <- Rplus_Or.
+Apply Rle_compatibility.
+Left; Apply Rmult_lt_pos.
+Apply Rlt_Rinv.
+Apply Rlt_anti_compatibility with x.
+Rewrite Rplus_Or.
+Replace ``x+(1-x)`` with R1; [Elim H3; Intros; Assumption | Ring].
+Apply H.
+Replace (sum_f_R0 An x2) with (Rplus (sum_f_R0 An x0) (sum_f_R0 [i:nat](An (plus (S x0) i)) (minus x2 (S x0)))).
+Apply Rle_compatibility.
+2:Symmetry.
+2:Apply tech2.
+2:Assumption.
+Cut (Rle (sum_f_R0 [i:nat](An (plus (S x0) i)) (minus x2 (S x0))) (Rmult (An (S x0)) (sum_f_R0 [i:nat](pow x i) (minus x2 (S x0))))).
+Intro.
+Apply Rle_trans with (Rmult (An (S x0)) (sum_f_R0 [i:nat](pow x i) (minus x2 (S x0)))).
+Assumption.
+Rewrite <- (Rmult_sym (An (S x0))).
+Apply Rle_monotony.
+Left; Apply H.
+Rewrite tech3.
+Unfold Rdiv.
+Apply Rle_monotony_contra with ``1-x``.
+Apply Rlt_anti_compatibility with x; Rewrite Rplus_Or.
+Replace ``x+(1-x)`` with R1; [Elim H3; Intros; Assumption | Ring].
+Do 2 Rewrite (Rmult_sym ``1-x``).
+Rewrite Rmult_assoc.
+Rewrite <- Rinv_l_sym.
+Rewrite Rmult_1r.
+Apply Rle_anti_compatibility with ``(pow x (S (minus x2 (S x0))))``.
+Replace ``(pow x (S (minus x2 (S x0))))+(1-(pow x (S (minus x2 (S x0)))))`` with R1; [Idtac | Ring].
+Rewrite <- (Rplus_sym R1).
+Pattern 1 R1; Rewrite <- Rplus_Or.
+Apply Rle_compatibility.
+Left; Apply pow_lt.
+Apply Rle_lt_trans with k.
+Elim Hyp; Intros; Assumption.
+Elim H3; Intros; Assumption.
+Apply Rminus_eq_contra.
+Red; Intro.
+Elim H3; Intros.
+Rewrite H10 in H12; Elim (Rlt_antirefl ? H12).
+Red; Intro.
+Elim H3; Intros.
+Rewrite H10 in H12; Elim (Rlt_antirefl ? H12).
+Replace (An (S x0)) with (An (plus (S x0) O)).
+Apply (tech6 [i:nat](An (plus (S x0) i)) x).
+Left; Apply Rle_lt_trans with k.
+Elim Hyp; Intros; Assumption.
+Elim H3; Intros; Assumption.
+2:Replace (plus (S x0) O) with (S x0); [Reflexivity | Ring].
+Intro.
+Cut (n:nat)(ge n x0)->``(An (S n))<x*(An n)``.
+Intro.
+Replace (plus (S x0) (S i)) with (S (plus (S x0) i)).
+Apply H9.
+Unfold ge.
+Apply tech8.
+Cut (m:nat)(S m)=(plus m (1)); [Intro | Intro; Ring].
+Rewrite H10.
+Rewrite (H10 x0).
+Rewrite (H10 i).
+Ring.
+Intros.
+Apply Rlt_monotony_contra with ``/(An n)``.
+Apply Rlt_Rinv; Apply H.
+Do 2 Rewrite (Rmult_sym ``/(An n)``).
+Rewrite Rmult_assoc.
+Rewrite <- Rinv_r_sym.
+Rewrite Rmult_1r.
+Replace ``(An (S n))*/(An n)`` with ``(Rabsolu ((An (S n))/(An n)))``.
+Apply H5; Assumption.
+Rewrite Rabsolu_right.
+Unfold Rdiv; Reflexivity.
+Left; Unfold Rdiv; Change ``0<(An (S n))*/(An n)``; Apply Rmult_lt_pos.
+Apply H.
+Apply Rlt_Rinv; Apply H.
+Red; Intro.
+Assert H11 := (H n).
+Rewrite H10 in H11; Elim (Rlt_antirefl ? H11).
+Intro.
+Elim X; Intros.
+Apply Specif.existT with x.
+Apply tech10.
+2:Assumption.
+Unfold Un_growing.
+Intro.
+Rewrite tech5.
+Pattern 1 (sum_f_R0 An n); Rewrite <- Rplus_Or.
+Apply Rle_compatibility.
+Left; Apply H.
+Qed.