`sig
module Tree :
sig
type t
module V :
sig
type t
type label
val create : label -> t
val label : t -> label
val hash : t -> int
val equal : t -> t -> bool
end
module E :
sig
type t
val compare : t -> t -> int
type vertex = V.t
val src : t -> vertex
val dst : t -> vertex
type label = unit
val create : vertex -> label -> vertex -> t
val label : t -> label
end
val create : ?size:int -> unit -> t
val add_vertex : t -> V.t -> unit
val add_edge_e : t -> E.t -> unit
end
type t
val get_structure : DGraphSubTree.S.t -> DGraphSubTree.S.Tree.t
val get_root : DGraphSubTree.S.t -> DGraphSubTree.S.Tree.V.t
val get_tree_vertices :
DGraphSubTree.S.Tree.V.label ->
DGraphSubTree.S.t -> DGraphSubTree.S.Tree.V.t list
val is_ghost_node : DGraphSubTree.S.Tree.V.t -> DGraphSubTree.S.t -> bool
val is_ghost_edge : DGraphSubTree.S.Tree.E.t -> DGraphSubTree.S.t -> bool
exception Ghost_node
val get_graph_vertex :
DGraphSubTree.S.Tree.V.t ->
DGraphSubTree.S.t -> DGraphSubTree.S.Tree.V.label
end`