+type 'a clause =
+ int
+ * ('a literal * bool) list (* left hand side of the arrow,
+ with flag for selection *)
+ * ('a literal * bool) list (* right hand side of the arrow,
+ with flag for selection *)
+ * varlist
+ * 'a proof
+
+type 'a passive_clause = int * 'a clause (* weight * equation *)
+
+val vars_of_term : ?start_acc:int list -> 'a foterm -> int list