(*+ Intuition of "good oracle" rule *)

Lemma safeN_oracle_step_ n m l k R mlock :
islock l R m ->
R mlock ->
(forall Ω, safeN_ oracle_at_ext_old (S n) Ω (acquire l k) m) ->
forall m', Hrel n m m' ->
(forall Ω, safeN_  oracle_at_ext_old n Ω k m').