Definition rmap_age1 (k:rmap) : option rmap :=
    match unsquash k with
    | (O,_) => None
    | (S n,x) => Some (squash (n,x))
    end.Definition rmap_unage (k:rmap) : rmap :=
    match unsquash k with
    | (n,x) => squash (S n, x)
    end.

Lemma rmap_level_eq: @level rmap ag_rmap = fun x => fst (unsquash x).