X-Git-Url: http://matita.cs.unibo.it/gitweb/?a=blobdiff_plain;f=helm%2Fsoftware%2Fcomponents%2Fng_paramodulation%2Fsuperposition.ml;h=61d6c0589f3ab9952e670ead382f71633ea00ef8;hb=1c9b8f3ba2c86446d44160ae494bc85624bc5eaf;hp=eaa8f5428bec3a823c9795023b09bc103ec56783;hpb=05a0f788cd5758eaac6de65e7bc3ca98ee5c8d8f;p=helm.git

diff --git a/helm/software/components/ng_paramodulation/superposition.ml b/helm/software/components/ng_paramodulation/superposition.ml
index eaa8f5428..61d6c0589 100644
--- a/helm/software/components/ng_paramodulation/superposition.ml
+++ b/helm/software/components/ng_paramodulation/superposition.ml
@@ -178,12 +178,13 @@ module Superposition (B : Terms.Blob) =
     ;;
 
     (* move away *)
-    let is_identity_clause = function
+    let is_identity_clause ~unify = function
       | _, Terms.Equation (_,_,_,Terms.Eq), _, _ -> true
-      | _, Terms.Equation (l,r,_,_), vl, proof ->
+      | _, Terms.Equation (l,r,_,_), vl, proof when unify ->
 	  (try ignore(Unif.unification vl [] l r); true
 	  with FoUnif.UnificationFailure _ -> false)
       | _, Terms.Predicate _, _, _ -> assert false	  
+      | _ -> false
     ;;
 
     let build_new_clause bag maxvar filter rule t subst vl id id2 pos dir =
@@ -266,7 +267,7 @@ module Superposition (B : Terms.Blob) =
     (* demodulate and check for subsumption *)
     let simplify table maxvar bag clause = 
       let bag, clause = demodulate bag clause table in
-      if is_identity_clause clause then None
+      if is_identity_clause ~unify:false clause then None
       else
         match is_subsumed ~unify:false bag maxvar clause table with
 	  | None -> Some (bag, clause)
@@ -372,7 +373,7 @@ module Superposition (B : Terms.Blob) =
     (* this is like simplify but raises Success *)
     let simplify_goal maxvar table bag g_actives clause = 
       let bag, clause = demodulate bag clause table in
-      if (is_identity_clause clause)
+      if (is_identity_clause ~unify:true clause)
       then raise (Success (bag, maxvar, clause))
       else match is_subsumed ~unify:true bag maxvar clause table with
 	| None ->