+let is_eq_clause (_,l,_,_) =
+ match l with
+ | Equation _ -> true
+ | Predicate _ -> false
+;;
+
+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
+;;