(* * Copyright (c) 2009 Robert Dockins and Aquinas Hobor. * *)
(* Coq development: using indirection theory to model types in l-calculus *)
(* lam_ref_mach_lemmas.v: various boring lemmas about the machine *)
(* COERCIONS *)
(* DECIDABILTY *)
(* SUBSTITUTION *)

Lemma subst_subst_neq : forall e n m v1 v2,
n <> m ->
subst n v1 (subst m v2 e) =
subst m v2 (subst n v1 e).