Module ext_invert (subst : ext_subst_sig) <: ext_invert_sig.
Include subst.
Set Bullet Behavior "Strict Subproofs".
Set Implicit Arguments.

Lemma invert_a_Var :
forall G x A, Typing G (a_Var_f x) A -> exists A', binds x (Tm A') G /\ DefEq G (dom G) A A' a_Star.