matita/matita/contribs/lambdadelta/basic_2/i_dynamic/ntas.ma

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  14
  15 include "basic_2/notation/relations/colon_7.ma".
  16 include "basic_2/notation/relations/colon_6.ma".
  17 include "basic_2/notation/relations/colonstar_6.ma".
  18 include "basic_2/dynamic/cnv.ma".
  19
  20 (* ITERATED NATIVE TYPE ASSIGNMENT FOR TERMS ********************************)
  21
  22 definition ntas (a) (h) (n) (G) (L): relation term ≝ λT,U.
  23            ∃∃U0. ⦃G,L⦄ ⊢ U ![a,h] & ⦃G,L⦄ ⊢ T ![a,h] & ⦃G,L⦄ ⊢ U ➡*[h] U0 & ⦃G,L⦄ ⊢ T ➡*[n,h] U0.
  24
  25 interpretation "iterated native type assignment (term)"
  26    'Colon a h n G L T U = (ntas a h n G L T U).
  27
  28 interpretation "restricted iterated native type assignment (term)"
  29    'Colon h n G L T U = (ntas true h n G L T U).
  30
  31 interpretation "extended iterated native type assignment (term)"
  32    'ColonStar h n G L T U = (ntas false h n G L T U).
  33
  34 (* Basic properties *********************************************************)
  35
  36 lemma ntas_refl (a) (h) (G) (L):
  37       ∀T. ⦃G,L⦄ ⊢ T ![a,h] → ⦃G,L⦄ ⊢ T :[a,h,0] T.
  38 /2 width=3 by ex4_intro/ qed.