type comparison = Lt | Eq | Gt | Incomparable
-type rule = SuperpositionRight | SuperpositionLeft | Demodulation
+type rule = Superposition | Demodulation
type direction = Left2Right | Right2Left | Nodir
type position = int list
val pp : t -> string
val embed : t -> t foterm
val saturate : t -> t -> t foterm * t foterm
+ val mk_proof : t bag -> int -> int list -> t
end