X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fng_paramodulation%2Findex.ml;fp=helm%2Fsoftware%2Fcomponents%2Fng_paramodulation%2Findex.ml;h=4db4584a451494caf00bff8166a3a37f96d678dc;hb=5642a453e8b4bbe228d126aa0c44d31e101969ec;hp=3179f000068897755b450fcc8c315cc051c597ce;hpb=50b3acd4b20269cf615bb297262f0238cc8e692a;p=helm.git

diff --git a/helm/software/components/ng_paramodulation/index.ml b/helm/software/components/ng_paramodulation/index.ml
index 3179f0000..4db4584a4 100644
--- a/helm/software/components/ng_paramodulation/index.ml
+++ b/helm/software/components/ng_paramodulation/index.ml
@@ -80,12 +80,6 @@ module Index(B : Orderings.Blob) = struct
       type data = ClauseSet.elt and 
       type dataset = ClauseSet.t
     = Make(FotermIndexable)(ClauseSet)
-
-  let are_invertible maxvar varlist l r =
-    let _,_,subst = U.relocate maxvar varlist FoSubst.id_subst in
-    let l = FoSubst.apply_subst subst l in
-      try (ignore(Unif.alpha_eq l r);true) with
-	  FoUnif.UnificationFailure _ -> false
   
   let index_unit_clause maxvar t = function
     | (_,Terms.Equation (l,_,_,Terms.Gt),_,_) as c -> 
@@ -101,6 +95,8 @@ module Index(B : Orderings.Blob) = struct
           DT.index  
            (DT.index t l (Terms.Left2Right, c))
            r (Terms.Right2Left, c)
+    | (_,Terms.Equation (l,r,_,Terms.Invertible),vl,_) as c ->
+	DT.index t l (Terms.Left2Right, c)
     | (_,Terms.Equation (_,r,_,Terms.Eq),_,_)  -> assert false
     | (_,Terms.Predicate p,_,_) as c ->
           DT.index t p (Terms.Nodir, c)