matita/matita/lib/lambda/levels/term.ma

   1 (**************************************************************************)
   2 (*       ___                                                              *)
   3 (*      ||M||                                                             *)
   4 (*      ||A||       A project by Andrea Asperti                           *)
   5 (*      ||T||                                                             *)
   6 (*      ||I||       Developers:                                           *)
   7 (*      ||T||         The HELM team.                                      *)
   8 (*      ||A||         http://helm.cs.unibo.it                             *)
   9 (*      \   /                                                             *)
  10 (*       \ /        This file is distributed under the terms of the       *)
  11 (*        v         GNU General Public License Version 2                  *)
  12 (*                                                                        *)
  13 (**************************************************************************)
  14
  15 include "lambda/background/preamble.ma".
  16
  17 include "lambda/notation/functions/variablereferencebylevel_2.ma".
  18 include "lambda/notation/functions/application_3.ma".
  19
  20 (* PER LEVEL TERM STRUCTURE *************************************************)
  21
  22 (* Policy: term metavariables          : A, B, C, D, M, N
  23            relative level metavariables: i, j
  24            absolute level metavariables: d, e
  25 *)
  26 (* Bote: first argument: relative level of the term *)
  27 inductive lterm: Type[0] ≝
  28 | LVRef: nat  → nat  → lterm          (* variable reference by level *)
  29 | LAppl: nat  → lterm → lterm → lterm (* function application        *)
  30 .
  31
  32 interpretation "stratified term construction (variable reference by level)"
  33    'VariableReferenceByLevel i d = (LVRef i d).
  34
  35 interpretation "stratified term construction (application)"
  36    'Application i C A = (LAppl i C A).