X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fng_paramodulation%2Fterms.ml;h=3947107eab8bfeea1ba1866f49b60fd9e3328e68;hb=fcbe3e8f67fa42c84a57e343ba5ef6a97ba8ca67;hp=169d19b80b68a52d0eb062162464e451a96a5757;hpb=772def9075b7b62870ebf4cecec6bcd37a549b1d;p=helm.git

diff --git a/helm/software/components/ng_paramodulation/terms.ml b/helm/software/components/ng_paramodulation/terms.ml
index 169d19b80..3947107ea 100644
--- a/helm/software/components/ng_paramodulation/terms.ml
+++ b/helm/software/components/ng_paramodulation/terms.ml
@@ -18,7 +18,7 @@ type 'a foterm =
 
 type 'a substitution = (int * 'a foterm) list
 
-type comparison = Lt | Eq | Gt | Incomparable
+type comparison = Lt | Eq | Gt | Incomparable | Invertible
 
 type rule = Superposition | Demodulation
 type direction = Left2Right | Right2Left | Nodir
@@ -47,6 +47,14 @@ type 'a unit_clause =
 type 'a passive_clause = int * 'a unit_clause (* weight * equation *)
 
 
+let vars_of_term t =
+  let rec aux acc = function
+    | Leaf _ -> acc
+    | Var i -> if (List.mem i acc) then acc else i::acc
+    | Node l -> List.fold_left aux acc l
+  in aux [] t
+;;
+
 module OT =
  struct
    type t = int