Definition NoneP := SomeP ((Void:Type)::nil) (fun _ => FF).
Definition hair := preds.
Inductive resource : Type :=
| NO
| YES: pshare -> kind -> preds -> resource
| PURE: kind -> preds -> resource.
Definition res_option (r:resource) :=
match r with
| NO => None
| YES sh k _ => Some (sh,k)
| PURE k _ => None
end.
Inductive res_join : resource -> resource -> resource -> Prop :=
| res_join_NO1 : res_join NO NO NO
| res_join_NO2 : forall sh k p, res_join (YES sh k p) NO (YES sh k p)
| res_join_NO3 : forall sh k p, res_join NO (YES sh k p) (YES sh k p)
| res_join_YES : forall (sh1 sh2 sh3:pshare) k p,
join sh1 sh2 sh3 ->
res_join (YES sh1 k p) (YES sh2 k p) (YES sh3 k p)
| res_join_PURE : forall k p, res_join (PURE k p) (PURE k p) (PURE k p).
Instance Join_resource: Join resource := res_join.

Axiom rmapj_valid_join : forall (x y z : address -> resource),
join x y z -> valid x -> valid y -> valid z.