matita/matita/contribs/lambdadelta/basic_2/etc/unfold/unfold.etc

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  14
  15 include "basic_2/notation/relations/unfold_4.ma".
  16 include "basic_2/grammar/lenv_append.ma".
  17 include "basic_2/grammar/genv.ma".
  18 include "basic_2/substitution/drop.ma".
  19
  20 (* CONTEXT-SENSITIVE UNFOLD FOR TERMS ***************************************)
  21
  22 (* activate genv *)
  23 inductive unfold: relation4 genv lenv term lenv ≝
  24 | unfold_sort: ∀G,L,s. unfold G L (⋆s) L
  25 | unfold_lref: ∀I,G,L1,L2,K1,K2,V,i. ⬇[i] L1 ≡ K1. ⓑ{I}V →
  26                unfold G K1 V K2 → ⬇[Ⓣ, |L2|, i] L2 ≡ K2 →
  27                unfold G L1 (#i) (L1@@L2)
  28 | unfold_bind: ∀a,I,G,L1,L2,V,T.
  29                unfold G (L1.ⓑ{I}V) T L2 → unfold G L1 (ⓑ{a,I}V.T) L2
  30 | unfold_flat: ∀I,G,L1,L2,V,T.
  31                unfold G L1 T L2 → unfold G L1 (ⓕ{I}V.T) L2
  32 .
  33
  34 interpretation "context-sensitive unfold (term)"
  35    'Unfold G L1 T L2 = (unfold G L1 T L2).