module type G =sig..end
type t
module V:Sig.ORDERED_TYPE
typevertex =V.t
val mem_vertex : t -> vertex -> bool
val succ : t -> vertex -> vertex list
val fold_vertex : (vertex -> 'a -> 'a) -> t -> 'a -> 'a
val fold_succ : (vertex -> 'a -> 'a) -> t -> vertex -> 'a -> 'a