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4 (* ||A|| A project by Andrea Asperti *)
6 (* ||I|| Developers: *)
7 (* ||T|| The HELM team. *)
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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".
20 (* ITERATED NATIVE TYPE ASSIGNMENT FOR TERMS ********************************)
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.
25 interpretation "iterated native type assignment (term)"
26 'Colon a h n G L T U = (ntas a h n G L T U).
28 interpretation "restricted iterated native type assignment (term)"
29 'Colon h n G L T U = (ntas true h n G L T U).
31 interpretation "extended iterated native type assignment (term)"
32 'ColonStar h n G L T U = (ntas false h n G L T U).
34 (* Basic properties *********************************************************)
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.