DGraphSubTree.S
module Tree : Tree with type E.label = unit
type t
val get_structure : t -> Tree.t
val get_root : t -> Tree.V.t
val get_tree_vertices : Tree.V.label -> t -> Tree.V.t list
val is_ghost_node : Tree.V.t -> t -> bool
val is_ghost_edge : Tree.E.t -> t -> bool
exception Ghost_node
val get_graph_vertex : Tree.V.t -> t -> Tree.V.label