(** *** Lemmas about invariants preserved by coresteps*)

(** Permission [decay] preserves disjointness*)
Lemma decay_disjoint:
forall m m' p
(Hdecay: decay m m')
(Hlt: permMapLt p (getMaxPerm m))
(Hdisjoint: permMapsDisjoint (getCurPerm m) p),
permMapsDisjoint (getCurPerm m') p.