Ltac do_map_arg :=
match goal with |- ?a = ?b =>
match a with context [map ?x _] =>
match b with context [map ?y _] => replace y with x; auto end end end.

Lemma age1_YES: forall phi phi' l sh k ,
age1 phi = Some phi' -> (phi @ l = YES sh k NoneP <-> phi' @ l = YES sh k NoneP).