Section GLOBALENV_PRINCIPLES.
Variable P: t -> Prop.

Lemma add_globals_unique_preserves:
forall id gl ge,
(forall ge id1 g, P ge -> In (id1, g) gl -> id1 <> id -> P (add_global ge (id1, g))) ->
~In id (map fst gl) -> P ge -> P (add_globals ge gl).