Library Common

We define here the tags for the two sorts of Fsub terms. This datatype is shared across all the developments and adequacy proofs, saving us the trouble of having to translate between different, isomorphic tag datatypes all the time.

Require Import Metatheory.

Inductive tag : Set :=
  | Typ : tag
  | Exp : tag.

Theorem eq_tag_dec : forall x y : tag, {x = y} + {x <> y}.