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

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  14
  15 include "basic_2/notation/relations/fleq_8.ma".
  16 include "basic_2/computation/lpxs.ma".
  17
  18 (* EQUIVALENT "BIG TREE" NORMAL FORMS ***************************************)
  19
  20 (* Note: this definition works but is not symmetric nor decidable *)
  21 definition fleq: ∀h. sd h → tri_relation genv lenv term ≝
  22                  λh,g,G1,L1,T1,G2,L2,T2.
  23                  ∧∧ G1 = G2 & ⦃G1, L1⦄ ⊢ ➡*[h, g] L2 & T1 = T2.
  24
  25 interpretation
  26    "equivalent 'big tree' normal forms (closure)"
  27    'FLEq h g G1 L1 T1 G2 L2 T2 = (fleq h g G1 L1 T1 G2 L2 T2).
  28
  29 (* Basic_properties *********************************************************)
  30
  31 lemma fleq_refl: ∀h,g. tri_reflexive … (fleq h g).
  32 /2 width=1 by and3_intro/ qed.