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

(** [permMapCoherence] is preserved by decay *)
Lemma decay_coherence :
forall (m m' : mem) (pmap : access_map)
(Hdecay: decay m m')
(Hlt: permMapLt pmap (getMaxPerm m))
(Hcoh: permMapCoherence (getCurPerm m) pmap),
permMapCoherence (getCurPerm m') pmap.