Remark poffset_monotone:
forall p q, pge p q -> pge (poffset p) (poffset q).
Remark provenance_monotone:
forall x y, vge x y -> pge (provenance x) (provenance y).

Lemma vnormalize_monotone:
forall chunk x y,
vge x y -> vge (vnormalize chunk x) (vnormalize chunk y).