Section STRONGER.
Context {cs: compspecs}.
Definition stronger {t: type} (v v': reptype t) : Prop :=
forall sh, data_at sh t v |-- data_at sh t v'.
Definition data_equal {t} v1 v2 := forall sh, data_at sh t v1 = data_at sh t v2.
Notation "X '>>>' Y" := (stronger X Y) (at level 60, no associativity).
Notation "X '===' Y" := (data_equal X Y) (at level 60, no associativity).

Lemma stronger_JMeq:
forall t t' a a' b b',
t=t' ->
@JMeq (reptype t) a (reptype t') a' ->
@JMeq (reptype t) b (reptype t') b' ->
a >>> b -> a' >>> b'.