matita/matita/contribs/lambdadelta/basic_2/unfold/unfold.ma

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  14
  15 include "basic_2/grammar/lenv_append.ma".
  16 include "basic_2/relocation/ldrop.ma".
  17
  18 (* CONTEXT-SENSITIVE UNFOLD FOR TERMS ***************************************)
  19
  20 inductive unfold: lenv → relation2 term lenv ≝
  21 | unfold_sort: ∀L,k. unfold L (⋆k) L
  22 | unfold_lref: ∀I,L1,L2,K1,K2,V,i. ⇩[0, i] L1 ≡ K1. ⓑ{I}V →
  23                unfold K1 V K2 → ⇩[|L2|, i] L2 ≡ K2 →
  24                unfold L1 (#i) (L1@@L2)
  25 | unfold_bind: ∀a,I,L1,L2,V,T.
  26                unfold (L1.ⓑ{I}V) T L2 → unfold L1 (ⓑ{a,I}V.T) L2
  27 | unfold_flat: ∀I,L1,L2,V,T.
  28                unfold L1 T L2 → unfold L1 (ⓕ{I}V.T) L2
  29 .
  30
  31 interpretation "context-sensitive unfold (term)"
  32    'Unwind L1 T L2 = (unfold L1 T L2).