# Module type Contraction.G

    module type G = sig .. end

Minimal graph signature for edge contraction algorithm

    type t

    module V: Sig.COMPARABLE

    type vertex = V.t

    module E: Sig.EDGE  with type vertex = vertex

    type edge = E.t

    val empty : t

    val add_edge_e : t -> edge -> t

    val fold_edges_e : (edge -> 'a -> 'a) -> t -> 'a -> 'a

    val fold_vertex : (vertex -> 'a -> 'a) -> t -> 'a -> 'a