Hint Resolve DefEq_weaken_available Iso_weaken_available.

(* Specifications: *)
Lemma typing_weakening_mutual:
(forall G0 a A,     Typing G0 a A ->
forall E F G, (G0 = F ++ G) -> Ctx (F ++ E ++ G) -> Typing (F ++ E ++ G) a A) /\
(forall G0 phi,     PropWff G0 phi ->
forall E F G, (G0 = F ++ G) -> Ctx (F ++ E ++ G) -> PropWff (F ++ E ++ G) phi) /\
(forall G0 D p1 p2, Iso G0 D p1 p2 ->
forall E F G, (G0 = F ++ G) -> Ctx (F ++ E ++ G) -> Iso (F ++ E ++ G) D p1 p2) /\
(forall G0 D A B T, DefEq G0 D A B T ->
forall E F G, (G0 = F ++ G) -> Ctx (F ++ E ++ G) -> DefEq (F ++ E ++ G) D A B T) /\
(forall G0,         Ctx G0 ->
forall E F G, (G0 = F ++ G) -> Ctx (F ++ E ++ G) -> Ctx (F ++ E ++ G)).