···7373 standard concrete directional graphs. But accessing predecessors and
7474 removing a vertex are faster. *)
75757676- (** Imperative Unlabeled, bidirectional graph. *)
7676+ (** Persistent Unlabeled, bidirectional graph. *)
7777 module ConcreteBidirectional (V: COMPARABLE) :
7878 Sig.P with type V.t = V.t and type V.label = V.t and type E.t = V.t * V.t
7979 and type E.label = unit
80808181- (** Imperative Labeled and bidirectional graph. *)
8181+ (** Persistent Labeled and bidirectional graph. *)
8282 module ConcreteBidirectionalLabeled(V:COMPARABLE)(E:ORDERED_TYPE_DFT) :
8383 Sig.P with type V.t = V.t and type V.label = V.t
8484 and type E.t = V.t * E.t * V.t and type E.label = E.t