matita/matita/contribs/lambdadelta/ground/etc/relocation/pstream_eq.etc

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  14
  15 include "ground/lib/stream_eq.ma".
  16 include "ground/relocation/rtmap_eq.ma".
  17
  18 (* RELOCATION P-STREAM ******************************************************)
  19
  20 (* Properties (specific) ******************************************************)
  21
  22 fact eq_inv_seq_aux: ∀f1,f2,p1,p2. p1⨮f1 ≡ p2⨮f2 → p1 = p2 ∧ f1 ≡ f2.
  23 #f1 #f2 #p1 #p2 @(pnat_ind_2 … p1 p2) -p1 -p2
  24 [ #p2 #H elim (gr_eq_inv_push_sn … H) -H [2,3: // ]
  25   #g1 #H1 #H elim (push_inv_seq_dx … H) -H /2 width=1 by conj/
  26 | #p1 #_ #H elim (gr_eq_inv_next_push … H) -H //
  27 | #p1 #p2 #IH #H lapply (gr_eq_inv_next_bi … H ????) -H [5:|*: // ]
  28   #H elim (IH H) -IH -H /2 width=1 by conj/
  29 ]
  30 qed-.
  31
  32 lemma eq_inv_seq: ∀g1,g2. g1 ≡ g2 → ∀f1,f2,p1,p2. p1⨮f1 = g1 → p2⨮f2 = g2 →
  33                   p1 = p2 ∧ f1 ≡ f2.
  34 /2 width=1 by eq_inv_seq_aux/ qed-.
  35
  36 corec lemma nstream_eq: ∀f1,f2. f1 ≡ f2 → f1 ≗ f2.
  37 * #p1 #f1 * #p2 #f2 #Hf cases (gr_eq_inv_gen … Hf) -Hf *
  38 #g1 #g2 #Hg #H1 #H2
  39 [ cases (push_inv_seq_dx … H1) -H1 * -p1 #H1
  40   cases (push_inv_seq_dx … H2) -H2 * -p2 #H2
  41   @stream_eq_cons /2 width=1 by/
  42 | cases (next_inv_seq_dx … H1) -H1 #m1 #H1 * -p1
  43   cases (next_inv_seq_dx … H2) -H2 #m2 #H2 * -p2
  44   cases (eq_inv_seq … Hg … H1 H2) -g1 -g2 #Hm #Hf
  45   @stream_eq_cons /2 width=1 by/
  46 ]
  47 qed-.
  48
  49 corec lemma nstream_inv_eq: ∀f1,f2. f1 ≗ f2 → f1 ≡ f2.
  50 * #p1 #f1 * #p2 #f2 #H cases (stream_eq_inv_cons ??? H) -H [|*: // ]
  51 #Hf * -p2 cases p1 -p1 /3 width=5 by gr_eq_next/
  52 #n @gr_eq_next /3 width=5 by stream_eq_cons/
  53 qed.
  54
  55 lemma eq_seq_id: ∀f1,f2. f1 ≡ f2 → ∀n. n⨮f1 ≡ n⨮f2.
  56 /4 width=1 by nstream_inv_eq, nstream_eq, stream_eq_cons/ qed.