Module ext_subst (weak : ext_weak_sig) <: ext_subst_sig.
Include weak.
induction G2; [ | inversion 1]; simpl; auto.
Qed.

Lemma binds_map_5: forall c A B T F c1 ,
binds c (Co (Eq A B T) ) F ->
binds c (Co (Eq (co_subst_co_tm g_Triv c1 A) (co_subst_co_tm g_Triv c1 B) (co_subst_co_tm g_Triv c1 T)) ) (map (co_subst_co_sort g_Triv c1) F).