sig
type t
type label
val max_capacity : Flow.FLOW.label -> Flow.FLOW.t
val min_capacity : Flow.FLOW.label -> Flow.FLOW.t
val flow : Flow.FLOW.label -> Flow.FLOW.t
val add : Flow.FLOW.t -> Flow.FLOW.t -> Flow.FLOW.t
val sub : Flow.FLOW.t -> Flow.FLOW.t -> Flow.FLOW.t
val zero : Flow.FLOW.t
val compare : Flow.FLOW.t -> Flow.FLOW.t -> int
end