(* * 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 *)
(* STEP RELATION *)

Lemma stepn_trans : forall n m st1 st2 st3,
stepn n st1 st2 ->
stepn m st2 st3 ->
stepn (n+m) st1 st3.