λ(nix : ../NixPrelude.dhall) →
  let min = ./min.dhall

  let Optional/map = ../Optional/map.dhall nix

  let listMin
      : List Natural → Optional Natural
      = λ(xs : List Natural) →
          Optional/map
            Natural
            Natural
            ( λ(n : Natural) →
                if    Natural/isZero n
                then  n
                else  List/fold Natural xs Natural min n
            )
            (List/head Natural xs)

  in  listMin