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

  let fix
      : ∀(t : Type) → (t → t) → t
      = nix.primops.fix

  let fixp
      : (Set → Set) → Set
      = nix.primops.`fix'`

  in  { fix, fixp }