matita/matita/contribs/lambdadelta/basic_2/reducibility/ysc.ma

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  14
  15 include "basic_2/static/ssta.ma".
  16 include "basic_2/reducibility/cpr.ma".
  17
  18 (* "BIG TREE" SUCCESSOR ON CLOSURES *****************************************)
  19
  20 inductive ysc (h) (g) (L1) (T1): relation2 lenv term ≝
  21 | ysc_fw  : ∀L2,T2. ♯{L2, T2} < ♯{L1, T1} → ysc h g L1 T1 L2 T2
  22 | ysc_cpr : ∀T2. L1 ⊢ T1 ➡ T2 → (T1 = T2 → ⊥) → ysc h g L1 T1 L1 T2
  23 | ysc_ssta: ∀T2,l. ⦃h, L1⦄ ⊢ T1 •[g, l + 1] T2 → ysc h g L1 T1 L1 T2
  24 .
  25
  26 interpretation
  27    "'big tree' successor (closure)"
  28    'BTSuccessor h g L1 T1 L2 T2 = (ysc h g L1 T1 L2 T2).