(* * 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_env_split : forall env1 env2 n e,
subst_env' n (env1 ++ env2) e =
subst_env' n env1 (subst_env' (length env1 + n) env2 e).