matita/matita/contribs/lambdadelta/basic_2/computation/cpre.ma

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  14
  15 include "basic_2/computation/cprs.ma".
  16 include "basic_2/computation/csn.ma".
  17
  18 (* CONTEXT-SENSITIVE PARALLEL EVALUATION ON TERMS **************************)
  19
  20 definition cpre: lenv → relation term ≝
  21                  λL,T1,T2. L ⊢ T1 ➡* T2 ∧ L ⊢ 𝐍⦃T2⦄.
  22
  23 interpretation "context-sensitive parallel evaluation (term)"
  24    'PEval L T1 T2 = (cpre L T1 T2).
  25
  26 (* Basic_properties *********************************************************)
  27
  28 (* Basic_1: was just: nf2_sn3 *)
  29 axiom csn_cpre: ∀h,g,L,T1. ⦃h, L⦄ ⊢ ⬊*[g] T1 → ∃T2. L ⊢ T1 ➡* 𝐍⦃T2⦄.
  30 (*
  31 #h #g #L #T1 #H @(csn_ind … H) -T1
  32 #T1 #_ #IHT1
  33 elim (cnr_dec L T1) /3 width=3/
  34 * #T #H1T1 #H2T1
  35 elim (IHT1 … H2T1) -IHT1 -H2T1 [2: /2 width=2/ ] #T2 * /4 width=3/
  36 qed.
  37 *)