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[helm.git] / helm / ocaml / tactics / fourierR.ml
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+(* Copyright (C) 2002, HELM Team.
+ * 
+ * This file is part of HELM, an Hypertextual, Electronic
+ * Library of Mathematics, developed at the Computer Science
+ * Department, University of Bologna, Italy.
+ * 
+ * HELM is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ * 
+ * HELM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HELM; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA  02111-1307, USA.
+ * 
+ * For details, see the HELM World-Wide-Web page,
+ * http://cs.unibo.it/helm/.
+ *)
+
+(* $Id$ *)
+
+
+(******************** THE FOURIER TACTIC ***********************)
+
+(* La tactique Fourier ne fonctionne de manière sûre que si les coefficients 
+des inéquations et équations sont entiers. En attendant la tactique Field.
+*)
+
+open Fourier
+open ProofEngineTypes
+
+
+let debug x = print_string ("____ "^x) ; flush stdout;;
+
+let debug_pcontext x = 
+ let str = ref "" in
+ List.iter (fun y -> match y with Some(Cic.Name(a),_) -> str := !str ^ 
+  a ^ " " | _ ->()) x ;
+ debug ("contesto : "^ (!str) ^ "\n")
+;;
+
+(******************************************************************************
+Operations on linear combinations.
+
+Opérations sur les combinaisons linéaires affines.
+La partie homogène d'une combinaison linéaire est en fait une table de hash 
+qui donne le coefficient d'un terme du calcul des constructions, 
+qui est zéro si le terme n'y est pas. 
+*)
+
+
+
+(**
+        The type for linear combinations
+*)
+type flin = {fhom:(Cic.term , rational)Hashtbl.t;fcste:rational}             
+;;
+
+(**
+        @return an empty flin
+*)
+let flin_zero () = {fhom = Hashtbl.create 50;fcste=r0}
+;;
+
+(**
+        @param f a flin
+        @param x a Cic.term
+        @return the rational associated with x (coefficient)
+*)
+let flin_coef f x = 
+        try
+                (Hashtbl.find f.fhom x)
+        with
+                _ -> r0
+;;
+                        
+(**
+        Adds c to the coefficient of x
+        @param f a flin
+        @param x a Cic.term
+        @param c a rational
+        @return the new flin
+*)
+let flin_add f x c = 
+    match x with
+    Cic.Rel(n) ->(
+      let cx = flin_coef f x in
+      Hashtbl.remove f.fhom x;
+      Hashtbl.add f.fhom x (rplus cx c);
+      f)
+    |_->debug ("Internal error in Fourier! this is not a Rel "^CicPp.ppterm x^"\n");
+      let cx = flin_coef f x in
+      Hashtbl.remove f.fhom x;
+      Hashtbl.add f.fhom x (rplus cx c);
+      f
+;;
+(**
+        Adds c to f.fcste
+        @param f a flin
+        @param c a rational
+        @return the new flin
+*)
+let flin_add_cste f c =              
+    {fhom=f.fhom;
+     fcste=rplus f.fcste c}
+;;
+
+(**
+        @return a empty flin with r1 in fcste
+*)
+let flin_one () = flin_add_cste (flin_zero()) r1;;
+
+(**
+        Adds two flin
+*)
+let flin_plus f1 f2 = 
+    let f3 = flin_zero() in
+    Hashtbl.iter (fun x c -> let _=flin_add f3 x c in ()) f1.fhom;
+    Hashtbl.iter (fun x c -> let _=flin_add f3 x c in ()) f2.fhom;
+    flin_add_cste (flin_add_cste f3 f1.fcste) f2.fcste;
+;;
+
+(**
+        Substracts two flin
+*)
+let flin_minus f1 f2 = 
+    let f3 = flin_zero() in
+    Hashtbl.iter (fun x c -> let _=flin_add f3 x c in ()) f1.fhom;
+    Hashtbl.iter (fun x c -> let _=flin_add f3 x (rop c) in ()) f2.fhom;
+    flin_add_cste (flin_add_cste f3 f1.fcste) (rop f2.fcste);
+;;
+
+(**
+        @return a times f
+*)
+let flin_emult a f =
+    let f2 = flin_zero() in
+    Hashtbl.iter (fun x c -> let _=flin_add f2 x (rmult a c) in ()) f.fhom;
+    flin_add_cste f2 (rmult a f.fcste);
+;;
+
+   
+(*****************************************************************************)
+
+
+(**
+        @param t a term
+        @raise Failure if conversion is impossible
+        @return rational proiection of t
+*)
+let rec rational_of_term t =
+  (* fun to apply f to the first and second rational-term of l *)
+  let rat_of_binop f l =
+          let a = List.hd l and
+            b = List.hd(List.tl l) in
+        f (rational_of_term a) (rational_of_term b)
+  in
+  (* as before, but f is unary *)
+  let rat_of_unop f l =
+          f (rational_of_term (List.hd l))
+  in
+  match t with
+  | Cic.Cast (t1,t2) -> (rational_of_term t1)
+  | Cic.Appl (t1::next) ->
+        (match t1 with
+           Cic.Const (u,boh) ->
+            if UriManager.eq u HelmLibraryObjects.Reals.ropp_URI then
+                      rat_of_unop rop next 
+            else if UriManager.eq u HelmLibraryObjects.Reals.rinv_URI then
+                      rat_of_unop rinv next 
+            else if UriManager.eq u HelmLibraryObjects.Reals.rmult_URI then
+                      rat_of_binop rmult next
+            else if UriManager.eq u HelmLibraryObjects.Reals.rdiv_URI then
+                      rat_of_binop rdiv next
+            else if UriManager.eq u HelmLibraryObjects.Reals.rplus_URI then
+                      rat_of_binop rplus next
+            else if UriManager.eq u HelmLibraryObjects.Reals.rminus_URI then
+                      rat_of_binop rminus next
+            else failwith "not a rational"
+          | _ -> failwith "not a rational")
+  | Cic.Const (u,boh) ->
+        if UriManager.eq u HelmLibraryObjects.Reals.r1_URI then r1
+        else if UriManager.eq u HelmLibraryObjects.Reals.r0_URI then r0
+        else failwith "not a rational"
+  |  _ -> failwith "not a rational"
+;;
+
+(* coq wrapper
+let rational_of_const = rational_of_term;;
+*)
+let fails f a =
+ try
+   let tmp = (f a) in
+   false
+ with 
+   _-> true
+ ;;
+
+let rec flin_of_term t =
+        let fl_of_binop f l =
+                let a = List.hd l and
+                    b = List.hd(List.tl l) in
+                f (flin_of_term a)  (flin_of_term b)
+        in
+  try(
+    match t with
+  | Cic.Cast (t1,t2) -> (flin_of_term t1)
+  | Cic.Appl (t1::next) ->
+        begin
+        match t1 with
+        Cic.Const (u,boh) ->
+            begin
+             if UriManager.eq u HelmLibraryObjects.Reals.ropp_URI then
+                  flin_emult (rop r1) (flin_of_term (List.hd next))
+             else if UriManager.eq u HelmLibraryObjects.Reals.rplus_URI then
+                  fl_of_binop flin_plus next 
+             else if UriManager.eq u HelmLibraryObjects.Reals.rminus_URI then
+                  fl_of_binop flin_minus next
+             else if UriManager.eq u HelmLibraryObjects.Reals.rmult_URI then
+                     begin
+                let arg1 = (List.hd next) and
+                    arg2 = (List.hd(List.tl next)) 
+                in
+                if fails rational_of_term arg1 
+                   then
+                   if fails rational_of_term arg2
+                      then
+                      ( (* prodotto tra 2 incognite ????? impossibile*)
+                      failwith "Sistemi lineari!!!!\n" 
+                      )
+                      else
+                      (
+                      match arg1 with
+                      Cic.Rel(n) -> (*trasformo al volo*)
+                                    (flin_add (flin_zero()) arg1 (rational_of_term arg2))
+                       |_-> (* test this *)
+                           let tmp = flin_of_term arg1 in
+                           flin_emult  (rational_of_term arg2) (tmp)
+                      )
+                   else
+                   if fails rational_of_term arg2
+                      then
+                      (
+                      match arg2 with
+                      Cic.Rel(n) -> (*trasformo al volo*)
+                                    (flin_add (flin_zero()) arg2 (rational_of_term arg1))
+                       |_-> (* test this *)
+                           let tmp = flin_of_term arg2 in
+                           flin_emult (rational_of_term arg1) (tmp)
+
+                      )
+                      else
+                      (  (*prodotto tra razionali*)
+                      (flin_add_cste (flin_zero()) (rmult (rational_of_term arg1) (rational_of_term arg2)))  
+                      )
+                          (*try
+                        begin
+                        (*let a = rational_of_term arg1 in
+                        debug("ho fatto rational of term di "^CicPp.ppterm arg1^
+                         " e ho ottenuto "^string_of_int a.num^"/"^string_of_int a.den^"\n");*)
+                        let a = flin_of_term arg1  
+                           try 
+                                begin
+                                let b = (rational_of_term arg2) in
+                                debug("ho fatto rational of term di "^CicPp.ppterm arg2^
+                                 " e ho ottenuto "^string_of_int b.num^"/"^string_of_int b.den^"\n");
+                                    (flin_add_cste (flin_zero()) (rmult a b))
+                                end
+                           with 
+                                _ -> debug ("ho fallito2 su "^CicPp.ppterm arg2^"\n");
+                                     (flin_add (flin_zero()) arg2 a)
+                        end
+                      with 
+                        _-> debug ("ho fallito1 su "^CicPp.ppterm arg1^"\n");
+                            (flin_add(flin_zero()) arg1 (rational_of_term arg2))
+                            *)
+                end
+            else if UriManager.eq u HelmLibraryObjects.Reals.rinv_URI then
+               let a=(rational_of_term (List.hd next)) in
+               flin_add_cste (flin_zero()) (rinv a)
+            else if UriManager.eq u HelmLibraryObjects.Reals.rdiv_URI then
+                    begin
+                      let b=(rational_of_term (List.hd(List.tl next))) in
+                       try 
+                        begin
+                        let a = (rational_of_term (List.hd next)) in
+                        (flin_add_cste (flin_zero()) (rdiv a b))
+                        end
+                       with 
+                        _-> (flin_add (flin_zero()) (List.hd next) (rinv b))
+                end
+            else assert false
+            end
+        |_ -> assert false
+        end
+  | Cic.Const (u,boh) ->
+        begin
+         if UriManager.eq u HelmLibraryObjects.Reals.r1_URI then flin_one ()
+         else if UriManager.eq u HelmLibraryObjects.Reals.r0_URI then flin_zero ()
+         else assert false
+        end
+  |_-> assert false)
+  with _ -> debug("eccezione = "^CicPp.ppterm t^"\n");flin_add (flin_zero()) t r1
+;;
+
+(* coq wrapper
+let flin_of_constr = flin_of_term;;
+*)
+
+(**
+        Translates a flin to (c,x) list
+        @param f a flin
+        @return something like (c1,x1)::(c2,x2)::...::(cn,xn)
+*)
+let flin_to_alist f =
+    let res=ref [] in
+    Hashtbl.iter (fun x c -> res:=(c,x)::(!res)) f;
+    !res
+;;
+
+(* Représentation des hypothèses qui sont des inéquations ou des équations.
+*)
+
+(**
+        The structure for ineq
+*)
+type hineq={hname:Cic.term; (* le nom de l'hypothèse *)
+            htype:string; (* Rlt, Rgt, Rle, Rge, eqTLR ou eqTRL *)
+            hleft:Cic.term;
+            hright:Cic.term;
+            hflin:flin;
+            hstrict:bool}
+;;
+
+(* Transforme une hypothese h:t en inéquation flin<0 ou flin<=0
+*)
+
+let ineq1_of_term (h,t) =
+    match t with (* match t *)
+       Cic.Appl (t1::next) ->
+         let arg1= List.hd next in
+         let arg2= List.hd(List.tl next) in
+         (match t1 with (* match t1 *)
+           Cic.Const (u,boh) ->
+             if UriManager.eq u HelmLibraryObjects.Reals.rlt_URI then
+                            [{hname=h;
+                           htype="Rlt";
+                           hleft=arg1;
+                           hright=arg2;
+                           hflin= flin_minus (flin_of_term arg1)
+                                             (flin_of_term arg2);
+                           hstrict=true}]
+             else if UriManager.eq u HelmLibraryObjects.Reals.rgt_URI then
+                           [{hname=h;
+                           htype="Rgt";
+                           hleft=arg2;
+                           hright=arg1;
+                           hflin= flin_minus (flin_of_term arg2)
+                                             (flin_of_term arg1);
+                           hstrict=true}]
+             else if UriManager.eq u HelmLibraryObjects.Reals.rle_URI then
+                           [{hname=h;
+                           htype="Rle";
+                           hleft=arg1;
+                           hright=arg2;
+                           hflin= flin_minus (flin_of_term arg1)
+                                             (flin_of_term arg2);
+                           hstrict=false}]
+             else if UriManager.eq u HelmLibraryObjects.Reals.rge_URI then
+                           [{hname=h;
+                           htype="Rge";
+                           hleft=arg2;
+                           hright=arg1;
+                           hflin= flin_minus (flin_of_term arg2)
+                                             (flin_of_term arg1);
+                           hstrict=false}]
+             else assert false
+          | Cic.MutInd (u,i,o) ->
+             if UriManager.eq u HelmLibraryObjects.Logic.eq_URI then
+                            let t0= arg1 in
+                           let arg1= arg2 in
+                           let arg2= List.hd(List.tl (List.tl next)) in
+                    (match t0 with
+                         Cic.Const (u,boh) ->
+                           if UriManager.eq u HelmLibraryObjects.Reals.r_URI then
+                         [{hname=h;
+                           htype="eqTLR";
+                           hleft=arg1;
+                           hright=arg2;
+                           hflin= flin_minus (flin_of_term arg1)
+                                             (flin_of_term arg2);
+                           hstrict=false};
+                          {hname=h;
+                           htype="eqTRL";
+                           hleft=arg2;
+                           hright=arg1;
+                           hflin= flin_minus (flin_of_term arg2)
+                                             (flin_of_term arg1);
+                           hstrict=false}]
+                          else assert false
+                        |_-> assert false)
+                  else assert false
+          |_-> assert false)(* match t1 *)
+        |_-> assert false (* match t *)
+;;
+(* coq wrapper 
+let ineq1_of_constr = ineq1_of_term;;
+*)
+
+(* Applique la méthode de Fourier à une liste d'hypothèses (type hineq)
+*)
+
+let rec print_rl l =
+ match l with
+ []-> ()
+ | a::next -> Fourier.print_rational a ; print_string " " ; print_rl next
+;;
+
+let rec print_sys l =
+ match l with
+ [] -> ()
+ | (a,b)::next -> (print_rl a;
+                 print_string (if b=true then "strict\n"else"\n");
+                print_sys next)
+ ;;
+
+(*let print_hash h =
+        Hashtbl.iter (fun x y -> print_string ("("^"-"^","^"-"^")")) h
+;;*)
+
+let fourier_lineq lineq1 = 
+   let nvar=ref (-1) in
+   let hvar=Hashtbl.create 50 in (* la table des variables des inéquations *)
+   List.iter (fun f ->
+               Hashtbl.iter (fun x c ->
+                                 try (Hashtbl.find hvar x;())
+                                 with _-> nvar:=(!nvar)+1;
+                                             Hashtbl.add hvar x (!nvar);
+                                          debug("aggiungo una var "^
+                                           string_of_int !nvar^" per "^
+                                            CicPp.ppterm x^"\n"))
+                            f.hflin.fhom)
+             lineq1;
+   (*print_hash hvar;*)
+   debug("Il numero di incognite e' "^string_of_int (!nvar+1)^"\n");
+   let sys= List.map (fun h->
+               let v=Array.create ((!nvar)+1) r0 in
+               Hashtbl.iter (fun x c -> v.(Hashtbl.find hvar x) <- c) 
+                  h.hflin.fhom;
+               ((Array.to_list v)@[rop h.hflin.fcste],h.hstrict))
+             lineq1 in
+   debug ("chiamo unsolvable sul sistema di "^ 
+    string_of_int (List.length sys) ^"\n");
+   print_sys sys;
+   unsolvable sys
+;;
+
+(*****************************************************************************
+Construction de la preuve en cas de succès de la méthode de Fourier,
+i.e. on obtient une contradiction.
+*)
+
+
+let _eqT = Cic.MutInd(HelmLibraryObjects.Logic.eq_URI, 0, []) ;;
+let _False = Cic.MutInd (HelmLibraryObjects.Logic.false_URI, 0, []) ;;
+let _not = Cic.Const (HelmLibraryObjects.Logic.not_URI,[]);;
+let _R0 = Cic.Const (HelmLibraryObjects.Reals.r0_URI,[]);;
+let _R1 = Cic.Const (HelmLibraryObjects.Reals.r1_URI,[]);;
+let _R = Cic.Const (HelmLibraryObjects.Reals.r_URI,[]);;
+let _Rfourier_eqLR_to_le=Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rfourier_eqLR_to_le.con"), []) ;;
+let _Rfourier_eqRL_to_le=Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rfourier_eqRL_to_le.con"), []) ;;
+let _Rfourier_ge_to_le  =Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rfourier_ge_to_le.con"), []) ;;
+let _Rfourier_gt_to_lt         =Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rfourier_gt_to_lt.con"), []) ;;
+let _Rfourier_le=Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rfourier_le.con"), []) ;;
+let _Rfourier_le_le =Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rfourier_le_le.con"), []) ;;
+let _Rfourier_le_lt =Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rfourier_le_lt.con"), []) ;;
+let _Rfourier_lt=Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rfourier_lt.con"), []) ;;
+let _Rfourier_lt_le =Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rfourier_lt_le.con"), []) ;;
+let _Rfourier_lt_lt =Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rfourier_lt_lt.con"), []) ;;
+let _Rfourier_not_ge_lt = Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rfourier_not_ge_lt.con"), []) ;;
+let _Rfourier_not_gt_le = Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rfourier_not_gt_le.con"), []) ;;
+let _Rfourier_not_le_gt = Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rfourier_not_le_gt.con"), []) ;;
+let _Rfourier_not_lt_ge = Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rfourier_not_lt_ge.con"), []) ;;
+let _Rinv  = Cic.Const (HelmLibraryObjects.Reals.rinv_URI, []);;
+let _Rinv_R1 = Cic.Const(HelmLibraryObjects.Reals.rinv_r1_URI, []);;
+let _Rle = Cic.Const (HelmLibraryObjects.Reals.rle_URI, []);;
+let _Rle_mult_inv_pos =  Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rle_mult_inv_pos.con"), []) ;;
+let _Rle_not_lt = Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rle_not_lt.con"), []) ;;
+let _Rle_zero_1 = Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rle_zero_1.con"), []) ;;
+let _Rle_zero_pos_plus1 =  Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rle_zero_pos_plus1.con"), []) ;;
+let _Rlt = Cic.Const (HelmLibraryObjects.Reals.rlt_URI, []);;
+let _Rlt_mult_inv_pos = Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rlt_mult_inv_pos.con"), []) ;;
+let _Rlt_not_le =  Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rlt_not_le.con"), []) ;;
+let _Rlt_zero_1 = Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rlt_zero_1.con"), []) ;;
+let _Rlt_zero_pos_plus1 = Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rlt_zero_pos_plus1.con"), []) ;;
+let _Rminus = Cic.Const (HelmLibraryObjects.Reals.rminus_URI, []);;
+let _Rmult = Cic.Const (HelmLibraryObjects.Reals.rmult_URI, []);;
+let _Rnot_le_le =Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rnot_le_le.con"), []) ;;
+let _Rnot_lt0 = Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rnot_lt0.con"), []) ;;
+let _Rnot_lt_lt =Cic.Const ((UriManager.uri_of_string 
+ "cic:/Coq/fourier/Fourier_util/Rnot_lt_lt.con"), []) ;;
+let _Ropp = Cic.Const (HelmLibraryObjects.Reals.ropp_URI, []);;
+let _Rplus = Cic.Const (HelmLibraryObjects.Reals.rplus_URI, []);;
+
+(******************************************************************************)
+
+let is_int x = (x.den)=1
+;;
+
+(* fraction = couple (num,den) *)
+let rec rational_to_fraction x= (x.num,x.den)
+;;
+    
+(* traduction -3 -> (Ropp (Rplus R1 (Rplus R1 R1)))
+*)
+
+let rec int_to_real_aux n =
+  match n with
+    0 -> _R0 (* o forse R0 + R0 ????? *)
+  | 1 -> _R1
+  | _ -> Cic.Appl [ _Rplus ; _R1 ; int_to_real_aux (n-1) ]
+;;        
+        
+
+let int_to_real n =
+   let x = int_to_real_aux (abs n) in
+   if n < 0 then
+           Cic.Appl [ _Ropp ; x ] 
+   else
+           x
+;;
+
+
+(* -1/2 -> (Rmult (Ropp R1) (Rinv (Rplus R1 R1)))
+*)
+
+let rational_to_real x =
+   let (n,d)=rational_to_fraction x in 
+   Cic.Appl [ _Rmult ; int_to_real n ; Cic.Appl [ _Rinv ; int_to_real d ]  ]
+;;
+
+(* preuve que 0<n*1/d
+*)
+
+let tac_zero_inf_pos (n,d) =
+ let tac_zero_inf_pos (n,d) status =
+   (*let cste = pf_parse_constr gl in*)
+   let pall str (proof,goal) t =
+     debug ("tac "^str^" :\n" );
+     let curi,metasenv,pbo,pty = proof in
+     let metano,context,ty = CicUtil.lookup_meta goal metasenv in
+     debug ("th = "^ CicPp.ppterm t ^"\n"); 
+     debug ("ty = "^ CicPp.ppterm ty^"\n"); 
+   in
+   let tacn=ref (mk_tactic (fun status -> 
+        pall "n0" status _Rlt_zero_1 ;
+        apply_tactic (PrimitiveTactics.apply_tac ~term:_Rlt_zero_1) status )) in
+   let tacd=ref (mk_tactic (fun status -> 
+        pall "d0" status _Rlt_zero_1 ;
+        apply_tactic (PrimitiveTactics.apply_tac ~term:_Rlt_zero_1) status )) in
+
+
+  for i=1 to n-1 do 
+       tacn:=(Tacticals.then_ 
+        ~start:(mk_tactic (fun status -> 
+          pall ("n"^string_of_int i) status _Rlt_zero_pos_plus1;
+          apply_tactic 
+           (PrimitiveTactics.apply_tac ~term:_Rlt_zero_pos_plus1)
+           status))
+        ~continuation:!tacn); 
+  done;
+  for i=1 to d-1 do
+       tacd:=(Tacticals.then_ 
+        ~start:(mk_tactic (fun status -> 
+          pall "d" status _Rlt_zero_pos_plus1 ;
+          apply_tactic 
+           (PrimitiveTactics.apply_tac ~term:_Rlt_zero_pos_plus1) status)) 
+        ~continuation:!tacd); 
+  done;
+
+debug("TAC ZERO INF POS\n");
+  apply_tactic 
+  (Tacticals.thens 
+    ~start:(PrimitiveTactics.apply_tac ~term:_Rlt_mult_inv_pos)
+    ~continuations:[!tacn ;!tacd ] )
+  status
+ in
+  mk_tactic (tac_zero_inf_pos (n,d))
+;;
+
+
+
+(* preuve que 0<=n*1/d
+*)
+let tac_zero_infeq_pos gl (n,d) =
+ let tac_zero_infeq_pos gl (n,d) status =
+  (*let cste = pf_parse_constr gl in*)
+  debug("inizio tac_zero_infeq_pos\n");
+  let tacn = ref 
+   (*(if n=0 then
+     (PrimitiveTactics.apply_tac ~term:_Rle_zero_zero ) 
+    else*)
+     (PrimitiveTactics.apply_tac ~term:_Rle_zero_1 )
+  (* ) *)
+   in
+   let tacd=ref (PrimitiveTactics.apply_tac ~term:_Rlt_zero_1 ) in
+   for i=1 to n-1 do 
+       tacn:=(Tacticals.then_ ~start:(PrimitiveTactics.apply_tac 
+        ~term:_Rle_zero_pos_plus1) ~continuation:!tacn); 
+   done;
+   for i=1 to d-1 do
+       tacd:=(Tacticals.then_ ~start:(PrimitiveTactics.apply_tac 
+        ~term:_Rlt_zero_pos_plus1) ~continuation:!tacd); 
+   done;
+   apply_tactic 
+    (Tacticals.thens 
+     ~start:(PrimitiveTactics.apply_tac ~term:_Rle_mult_inv_pos) 
+     ~continuations:[!tacn;!tacd]) status 
+ in
+  mk_tactic (tac_zero_infeq_pos gl (n,d))
+;;
+
+
+(* preuve que 0<(-n)*(1/d) => False 
+*)
+
+let tac_zero_inf_false gl (n,d) =
+ let tac_zero_inf_false gl (n,d) status =
+   if n=0 then 
+    apply_tactic (PrimitiveTactics.apply_tac ~term:_Rnot_lt0) status
+   else
+    apply_tactic (Tacticals.then_ 
+     ~start:( mk_tactic (fun status -> 
+       let (proof, goal) = status in
+       let curi,metasenv,pbo,pty = proof in
+       let metano,context,ty = CicUtil.lookup_meta goal metasenv in
+        apply_tactic (PrimitiveTactics.apply_tac ~term:_Rle_not_lt) status))
+     ~continuation:(tac_zero_infeq_pos gl (-n,d))) 
+    status
+ in
+  mk_tactic (tac_zero_inf_false gl (n,d))
+;;
+
+(* preuve que 0<=n*(1/d) => False ; n est negatif
+*)
+
+let tac_zero_infeq_false gl (n,d) =
+ let tac_zero_infeq_false gl (n,d) status =
+  let (proof, goal) = status in
+  let curi,metasenv,pbo,pty = proof in
+  let metano,context,ty = CicUtil.lookup_meta goal metasenv in
+  
+  debug("faccio fold di " ^ CicPp.ppterm
+         (Cic.Appl
+           [_Rle ; _R0 ;
+            Cic.Appl
+             [_Rmult ; int_to_real n ; Cic.Appl [_Rinv ; int_to_real d]]
+           ]
+         ) ^ "\n") ;
+  debug("apply di _Rlt_not_le a "^ CicPp.ppterm ty ^"\n");
+  (*CSC: Patch to undo the over-simplification of RewriteSimpl *)
+  apply_tactic 
+   (Tacticals.then_
+    ~start:
+      (ReductionTactics.fold_tac
+        ~reduction:(const_lazy_reduction CicReduction.whd)
+        ~pattern:(ProofEngineTypes.conclusion_pattern None)
+        ~term:
+          (const_lazy_term
+            (Cic.Appl
+            [_Rle ; _R0 ;
+              Cic.Appl
+               [_Rmult ; int_to_real n ; Cic.Appl [_Rinv ; int_to_real d]]])))
+    ~continuation:
+      (Tacticals.then_ 
+        ~start:(PrimitiveTactics.apply_tac ~term:_Rlt_not_le)
+        ~continuation:(tac_zero_inf_pos (-n,d))))
+   status 
+ in
+  mk_tactic (tac_zero_infeq_false gl (n,d))
+;;
+
+
+(* *********** ********** ******** ??????????????? *********** **************)
+
+let apply_type_tac ~cast:t ~applist:al = 
+ let apply_type_tac ~cast:t ~applist:al (proof,goal) = 
+  let curi,metasenv,pbo,pty = proof in
+  let metano,context,ty = CicUtil.lookup_meta goal metasenv in
+  let fresh_meta = ProofEngineHelpers.new_meta_of_proof proof in
+  let irl =
+   CicMkImplicit.identity_relocation_list_for_metavariable context in
+  let metasenv' = (fresh_meta,context,t)::metasenv in
+   let proof' = curi,metasenv',pbo,pty in
+    let proof'',goals =
+     apply_tactic 
+      (PrimitiveTactics.apply_tac 
+       (*~term:(Cic.Appl ((Cic.Cast (Cic.Meta (fresh_meta,irl),t))::al)) *)
+       ~term:(Cic.Appl ((Cic.Meta (fresh_meta,irl))::al))) (* ??? *)
+      (proof',goal)
+    in
+     proof'',fresh_meta::goals
+ in
+  mk_tactic (apply_type_tac ~cast:t ~applist:al)
+;;
+
+let my_cut ~term:c =
+ let my_cut ~term:c (proof,goal) =
+  let curi,metasenv,pbo,pty = proof in
+  let metano,context,ty = CicUtil.lookup_meta goal metasenv in
+  let fresh_meta = ProofEngineHelpers.new_meta_of_proof proof in
+  let irl =
+   CicMkImplicit.identity_relocation_list_for_metavariable context in
+  let metasenv' = (fresh_meta,context,c)::metasenv in
+   let proof' = curi,metasenv',pbo,pty in
+    let proof'',goals =
+     apply_tactic 
+      (apply_type_tac 
+       ~cast:(Cic.Prod(Cic.Name "Anonymous",c,CicSubstitution.lift 1 ty)) 
+       ~applist:[Cic.Meta(fresh_meta,irl)])
+      (proof',goal)
+    in
+     (* We permute the generated goals to be consistent with Coq *)
+     match goals with
+        [] -> assert false
+      | he::tl -> proof'',he::fresh_meta::tl
+ in
+  mk_tactic (my_cut ~term:c)
+;;
+
+let exact = PrimitiveTactics.exact_tac;;
+
+let tac_use h = 
+ let tac_use h status = 
+  let (proof, goal) = status in
+  debug("Inizio TC_USE\n");
+  let curi,metasenv,pbo,pty = proof in
+  let metano,context,ty = CicUtil.lookup_meta goal metasenv in
+  debug ("hname = "^ CicPp.ppterm h.hname ^"\n"); 
+  debug ("ty = "^ CicPp.ppterm ty^"\n");
+  apply_tactic 
+   (match h.htype with
+      "Rlt" -> exact ~term:h.hname 
+    | "Rle" -> exact ~term:h.hname 
+    | "Rgt" -> (Tacticals.then_ 
+                 ~start:(PrimitiveTactics.apply_tac ~term:_Rfourier_gt_to_lt) 
+                 ~continuation:(exact ~term:h.hname)) 
+    | "Rge" -> (Tacticals.then_ 
+                 ~start:(PrimitiveTactics.apply_tac ~term:_Rfourier_ge_to_le)
+                 ~continuation:(exact ~term:h.hname)) 
+    | "eqTLR" -> (Tacticals.then_ 
+                   ~start:(PrimitiveTactics.apply_tac ~term:_Rfourier_eqLR_to_le)
+                   ~continuation:(exact ~term:h.hname)) 
+    | "eqTRL" -> (Tacticals.then_ 
+                   ~start:(PrimitiveTactics.apply_tac ~term:_Rfourier_eqRL_to_le)
+                   ~continuation:(exact ~term:h.hname)) 
+    | _->assert false)
+   status
+ in
+  mk_tactic (tac_use h)
+;;
+
+let is_ineq (h,t) =
+    match t with
+       Cic.Appl ( Cic.Const(u,boh)::next) ->
+         (if UriManager.eq u HelmLibraryObjects.Reals.rlt_URI or
+             UriManager.eq u HelmLibraryObjects.Reals.rgt_URI or
+             UriManager.eq u HelmLibraryObjects.Reals.rle_URI or
+             UriManager.eq u HelmLibraryObjects.Reals.rge_URI then true
+          else if UriManager.eq u HelmLibraryObjects.Logic.eq_URI then
+                   (match (List.hd next) with
+                       Cic.Const (uri,_) when
+                        UriManager.eq uri HelmLibraryObjects.Reals.r_URI
+                         -> true
+                     | _ -> false)
+           else false)
+     |_->false
+;;
+
+let list_of_sign s = List.map (fun (x,_,z)->(x,z)) s;;
+
+let mkAppL a =
+   Cic.Appl(Array.to_list a)
+;;
+
+(* Résolution d'inéquations linéaires dans R *)
+let rec strip_outer_cast c = match c with
+  | Cic.Cast (c,_) -> strip_outer_cast c
+  | _ -> c
+;;
+
+(*let find_in_context id context =
+  let rec find_in_context_aux c n =
+          match c with
+        [] -> failwith (id^" not found in context")      
+        | a::next -> (match a with 
+                        Some (Cic.Name(name),_) when name = id -> n 
+                              (*? magari al posto di _ qualcosaltro?*)
+                        | _ -> find_in_context_aux next (n+1))
+  in 
+  find_in_context_aux context 1 
+;;
+
+(* mi sembra quadratico *)
+let rec filter_real_hyp context cont =
+  match context with
+  [] -> []
+  | Some(Cic.Name(h),Cic.Decl(t))::next -> (
+                                  let n = find_in_context h cont in
+                                debug("assegno "^string_of_int n^" a "^CicPp.ppterm t^"\n");
+                          [(Cic.Rel(n),t)] @ filter_real_hyp next cont)
+  | a::next -> debug("  no\n"); filter_real_hyp next cont
+;;*)
+
+let filter_real_hyp context _ =
+  let rec filter_aux context num =
+   match context with
+     [] -> []
+   | Some(Cic.Name(h),Cic.Decl(t))::next -> 
+       [(Cic.Rel(num),t)] @ filter_aux next (num+1)
+   | a::next -> filter_aux next (num+1)
+  in
+   filter_aux context 1
+;;
+
+
+(* lifts everithing at the conclusion level *)        
+let rec superlift c n=
+  match c with
+    [] -> []
+  | Some(name,Cic.Decl(a))::next  -> 
+     [Some(name,Cic.Decl(CicSubstitution.lift n a))]@ superlift next (n+1)
+  | Some(name,Cic.Def(a,None))::next -> 
+     [Some(name,Cic.Def((CicSubstitution.lift n a),None))]@ superlift next (n+1)
+  | Some(name,Cic.Def(a,Some ty))::next   -> 
+     [Some(name,
+      Cic.Def((CicSubstitution.lift n a),Some (CicSubstitution.lift n ty)))
+      ] @ superlift next (n+1)
+  | _::next -> superlift next (n+1) (*??  ??*)
+;;
+
+let equality_replace a b =
+ let equality_replace a b status =
+ debug("inizio EQ\n");
+  let module C = Cic in
+   let proof,goal = status in
+   let curi,metasenv,pbo,pty = proof in
+   let metano,context,ty = CicUtil.lookup_meta goal metasenv in
+    let a_eq_b = C.Appl [ _eqT ; _R ; a ; b ] in
+    let fresh_meta = ProofEngineHelpers.new_meta_of_proof proof in
+    let irl =
+     CicMkImplicit.identity_relocation_list_for_metavariable context in
+    let metasenv' = (fresh_meta,context,a_eq_b)::metasenv in
+ debug("chamo rewrite tac su"^CicPp.ppterm (C.Meta (fresh_meta,irl)));
+    let (proof,goals) = apply_tactic 
+     (EqualityTactics.rewrite_simpl_tac
+       ~direction:`LeftToRight
+       ~pattern:(ProofEngineTypes.conclusion_pattern None)
+       (C.Meta (fresh_meta,irl)))
+     ((curi,metasenv',pbo,pty),goal)
+    in
+    let new_goals = fresh_meta::goals in
+ debug("fine EQ -> goals : "^string_of_int( List.length new_goals)  ^" = "
+   ^string_of_int( List.length goals)^"+ meta\n");
+     (proof,new_goals)
+ in 
+  mk_tactic (equality_replace a b)
+;;
+
+let tcl_fail a (proof,goal) =
+  match a with
+    1 -> raise (ProofEngineTypes.Fail (lazy "fail-tactical"))
+  | _ -> (proof,[goal])
+;;
+
+(* Galla: moved in variousTactics.ml 
+let assumption_tac (proof,goal)=
+  let curi,metasenv,pbo,pty = proof in
+  let metano,context,ty = CicUtil.lookup_meta goal metasenv in
+  let num = ref 0 in
+  let tac_list = List.map 
+          ( fun x -> num := !num + 1;
+                match x with
+                  Some(Cic.Name(nm),t) -> (nm,exact ~term:(Cic.Rel(!num)))
+                  | _ -> ("fake",tcl_fail 1)
+        )  
+          context 
+  in
+  Tacticals.first ~tactics:tac_list (proof,goal)
+;;
+*)
+(* Galla: moved in negationTactics.ml
+(* !!!!! fix !!!!!!!!!! *)
+let contradiction_tac (proof,goal)=
+        Tacticals.then_ 
+                (*inutile sia questo che quello prima  della chiamata*)
+                ~start:PrimitiveTactics.intros_tac
+                ~continuation:(Tacticals.then_ 
+                        ~start:(VariousTactics.elim_type_tac ~term:_False) 
+                        ~continuation:(assumption_tac))
+        (proof,goal) 
+;;
+*)
+
+(* ********************* TATTICA ******************************** *)
+
+let rec fourier (s_proof,s_goal)=
+  let s_curi,s_metasenv,s_pbo,s_pty = s_proof in
+  let s_metano,s_context,s_ty = CicUtil.lookup_meta s_goal s_metasenv in
+  debug ("invoco fourier_tac sul goal "^string_of_int(s_goal)^" e contesto:\n");
+  debug_pcontext s_context;
+
+(* here we need to negate the thesis, but to do this we need to apply the 
+   right theoreme,so let's parse our thesis *)
+  
+  let th_to_appl = ref _Rfourier_not_le_gt in   
+  (match s_ty with
+   Cic.Appl ( Cic.Const(u,boh)::args) ->
+    th_to_appl :=
+    (if UriManager.eq u HelmLibraryObjects.Reals.rlt_URI then
+      _Rfourier_not_ge_lt
+     else if UriManager.eq u HelmLibraryObjects.Reals.rle_URI then
+               _Rfourier_not_gt_le
+     else if UriManager.eq u HelmLibraryObjects.Reals.rgt_URI then
+               _Rfourier_not_le_gt
+     else if UriManager.eq u HelmLibraryObjects.Reals.rge_URI then
+               _Rfourier_not_lt_ge
+     else failwith "fourier can't be applyed")
+   |_-> failwith "fourier can't be applyed"); 
+   (* fix maybe strip_outer_cast goes here?? *)
+
+   (* now let's change our thesis applying the th and put it with hp *) 
+
+   let proof,gl = apply_tactic 
+    (Tacticals.then_ 
+      ~start:(PrimitiveTactics.apply_tac ~term:!th_to_appl)
+      ~continuation:(PrimitiveTactics.intros_tac ()))
+    (s_proof,s_goal) 
+   in
+   let goal = if List.length gl = 1 then List.hd gl 
+                                    else failwith "a new goal" in
+
+   debug ("port la tesi sopra e la nego. contesto :\n");
+   debug_pcontext s_context;
+
+   (* now we have all the right environment *)
+   
+   let curi,metasenv,pbo,pty = proof in
+   let metano,context,ty = CicUtil.lookup_meta goal metasenv in
+
+   (* now we want to convert hp to inequations, but first we must lift
+      everyting to thesis level, so that a variable has the save Rel(n) 
+      in each hp ( needed by ineq1_of_term ) *)
+    
+    (* ? fix if None  ?????*)
+    (* fix change superlift with a real name *)
+
+  let l_context = superlift context 1 in
+  let hyps = filter_real_hyp l_context l_context in
+  
+  debug ("trasformo in diseq. "^ string_of_int (List.length hyps)^" ipotesi\n");
+  
+  let lineq =ref [] in
+  
+  (* transform hyps into inequations *)
+  
+  List.iter (fun h -> try (lineq:=(ineq1_of_term h)@(!lineq))
+                        with _-> ())
+              hyps;
+            
+  debug ("applico fourier a "^ string_of_int (List.length !lineq)^
+         " disequazioni\n");
+
+  let res=fourier_lineq (!lineq) in
+  let tac=ref Tacticals.id_tac in
+  if res=[] then 
+          (print_string "Tactic Fourier fails.\n";flush stdout;
+         failwith "fourier_tac fails")
+  else 
+  (
+  match res with (*match res*)
+  [(cres,sres,lc)]->
+  
+     (* in lc we have the coefficient to "reduce" the system *)
+     
+     print_string "Fourier's method can prove the goal...\n";flush stdout;
+         
+     debug "I coeff di moltiplicazione rit sono: ";
+     
+     let lutil=ref [] in
+     List.iter 
+        (fun (h,c) -> if c<>r0 then (lutil:=(h,c)::(!lutil);
+           (* DBG *)Fourier.print_rational(c);print_string " "(* DBG *))
+                                     )
+        (List.combine (!lineq) lc); 
+        
+     print_string (" quindi lutil e' lunga "^
+      string_of_int (List.length (!lutil))^"\n");                   
+       
+     (* on construit la combinaison linéaire des inéquation *)
+     
+     (match (!lutil) with (*match (!lutil) *)
+       (h1,c1)::lutil ->
+       debug ("elem di lutil ");Fourier.print_rational c1;print_string "\n"; 
+          
+       let s=ref (h1.hstrict) in
+          
+          
+       let t1 = ref (Cic.Appl [_Rmult;rational_to_real c1;h1.hleft] ) in
+       let t2 = ref (Cic.Appl [_Rmult;rational_to_real c1;h1.hright]) in
+
+       List.iter (fun (h,c) ->
+               s:=(!s)||(h.hstrict);
+               t1:=(Cic.Appl [_Rplus;!t1;Cic.Appl 
+                     [_Rmult;rational_to_real c;h.hleft ]  ]);
+               t2:=(Cic.Appl [_Rplus;!t2;Cic.Appl 
+                     [_Rmult;rational_to_real c;h.hright]  ]))
+               lutil;
+               
+       let ineq=Cic.Appl [(if (!s) then _Rlt else _Rle);!t1;!t2 ] in
+       let tc=rational_to_real cres in
+
+
+(* ora ho i termini che descrivono i passi di fourier per risolvere il sistema *)
+       
+       debug "inizio a costruire tac1\n";
+       Fourier.print_rational(c1);
+          
+       let tac1=ref ( mk_tactic (fun status -> 
+         apply_tactic
+          (if h1.hstrict then 
+           (Tacticals.thens 
+             ~start:(mk_tactic (fun status -> 
+              debug ("inizio t1 strict\n");
+              let curi,metasenv,pbo,pty = proof in
+              let metano,context,ty = CicUtil.lookup_meta goal metasenv in
+              debug ("th = "^ CicPp.ppterm _Rfourier_lt ^"\n"); 
+              debug ("ty = "^ CicPp.ppterm ty^"\n"); 
+              apply_tactic 
+               (PrimitiveTactics.apply_tac ~term:_Rfourier_lt) status))
+            ~continuations:[tac_use h1;
+              tac_zero_inf_pos (rational_to_fraction c1)])
+          else 
+           (Tacticals.thens 
+             ~start:(PrimitiveTactics.apply_tac ~term:_Rfourier_le)
+             ~continuations:[tac_use h1;tac_zero_inf_pos
+              (rational_to_fraction c1)]))
+          status))
+                   
+       in
+       s:=h1.hstrict;
+       List.iter (fun (h,c) -> 
+         (if (!s) then 
+           (if h.hstrict then 
+             (debug("tac1 1\n");
+             tac1:=(Tacticals.thens 
+               ~start:(PrimitiveTactics.apply_tac ~term:_Rfourier_lt_lt)
+               ~continuations:[!tac1;tac_use h;tac_zero_inf_pos
+                (rational_to_fraction c)]))
+            else 
+             (debug("tac1 2\n");
+             Fourier.print_rational(c1);
+             tac1:=(Tacticals.thens 
+              ~start:(mk_tactic (fun status -> 
+                debug("INIZIO TAC 1 2\n");
+                let curi,metasenv,pbo,pty = proof in
+                let metano,context,ty = CicUtil.lookup_meta goal metasenv in
+                debug ("th = "^ CicPp.ppterm _Rfourier_lt_le ^"\n"); 
+                debug ("ty = "^ CicPp.ppterm ty^"\n"); 
+                apply_tactic 
+                 (PrimitiveTactics.apply_tac ~term:_Rfourier_lt_le) 
+                 status))
+              ~continuations:[!tac1;tac_use h;tac_zero_inf_pos 
+                (rational_to_fraction c)])))
+          else 
+           (if h.hstrict then 
+             (debug("tac1 3\n");
+             tac1:=(Tacticals.thens 
+               ~start:(PrimitiveTactics.apply_tac ~term:_Rfourier_le_lt)
+               ~continuations:[!tac1;tac_use h;tac_zero_inf_pos  
+                (rational_to_fraction c)]))
+            else 
+             (debug("tac1 4\n");
+             tac1:=(Tacticals.thens 
+               ~start:(PrimitiveTactics.apply_tac ~term:_Rfourier_le_le)
+               ~continuations:[!tac1;tac_use h;tac_zero_inf_pos  
+                (rational_to_fraction c)]))));
+         s:=(!s)||(h.hstrict)) (* end fun -> *)
+         lutil;(*end List.iter*)
+                     
+       let tac2 = 
+         if sres then 
+           tac_zero_inf_false goal (rational_to_fraction cres)
+         else 
+           tac_zero_infeq_false goal (rational_to_fraction cres)
+       in
+       tac:=(Tacticals.thens 
+         ~start:(my_cut ~term:ineq) 
+         ~continuations:[Tacticals.then_  
+           ~start:( mk_tactic (fun status ->
+             let (proof, goal) = status in
+             let curi,metasenv,pbo,pty = proof in
+             let metano,context,ty = CicUtil.lookup_meta goal metasenv in
+             apply_tactic 
+              (ReductionTactics.change_tac
+                ~pattern:(ProofEngineTypes.conclusion_pattern (Some ty))
+                (const_lazy_term (Cic.Appl [ _not; ineq])))
+              status))
+           ~continuation:(Tacticals.then_ 
+             ~start:(PrimitiveTactics.apply_tac ~term:
+               (if sres then _Rnot_lt_lt else _Rnot_le_le))
+             ~continuation:(Tacticals.thens 
+               ~start:(mk_tactic (fun status ->
+                 debug("t1 ="^CicPp.ppterm !t1 ^"t2 ="^
+                  CicPp.ppterm !t2 ^"tc="^ CicPp.ppterm tc^"\n");
+                 let r = apply_tactic 
+                 (equality_replace (Cic.Appl [_Rminus;!t2;!t1] ) tc) 
+                  status
+                 in
+                 (match r with (p,gl) -> 
+                   debug("eq1 ritorna "^string_of_int(List.length gl)^"\n" ));
+                 r))
+               ~continuations:[(Tacticals.thens 
+                 ~start:(mk_tactic (fun status ->
+                   let r = apply_tactic 
+                   (equality_replace (Cic.Appl[_Rinv;_R1]) _R1) 
+                   status 
+                  in
+                   (match r with (p,gl) ->
+                     debug("eq2 ritorna "^string_of_int(List.length gl)^"\n" ));
+                   r))
+                 ~continuations:
+                   [PrimitiveTactics.apply_tac ~term:_Rinv_R1;
+                   Tacticals.first 
+                     ~tactics:[ "ring",Ring.ring_tac; "id", Tacticals.id_tac] 
+                   ])
+               ;(*Tacticals.id_tac*)
+                Tacticals.then_ 
+                 ~start:(mk_tactic (fun status ->
+                   let (proof, goal) = status in
+                   let curi,metasenv,pbo,pty = proof in
+                   let metano,context,ty = CicUtil.lookup_meta goal metasenv in
+                   (* check if ty is of type *)
+                   let w1 = 
+                     debug("qui c'e' gia' l'or "^CicPp.ppterm ty^"\n");
+                     (match ty with
+                     Cic.Prod (Cic.Anonymous,a,b) -> (Cic.Appl [_not;a])
+                     |_ -> assert false)
+                   in
+                   let r = apply_tactic 
+                   (ReductionTactics.change_tac
+                      ~pattern:(ProofEngineTypes.conclusion_pattern (Some ty))
+                      (const_lazy_term w1)) status
+                   in
+                   debug("fine MY_CHNGE\n");
+                   r)) 
+                 ~continuation:(*PORTINGTacticals.id_tac*)tac2]))
+         ;(*Tacticals.id_tac*)!tac1]);(*end tac:=*)
+
+    |_-> assert false)(*match (!lutil) *)
+  |_-> assert false); (*match res*)
+  debug ("finalmente applico tac\n");
+  (
+  let r = apply_tactic !tac (proof,goal) in
+  debug("\n\n]]]]]]]]]]]]]]]]]) That's all folks ([[[[[[[[[[[[[[[[[[[\n\n");r
+  
+  ) 
+;;
+
+let fourier_tac = mk_tactic fourier
+
+