helm/software/matita/contribs/ng_assembly/common/ascii_lemmas1.ma

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  14
  15 (* ********************************************************************** *)
  16 (*                          Progetto FreeScale                            *)
  17 (*                                                                        *)
  18 (*   Sviluppato da: Ing. Cosimo Oliboni, oliboni@cs.unibo.it              *)
  19 (*   Ultima modifica: 05/08/2009                                          *)
  20 (*                                                                        *)
  21 (* ********************************************************************** *)
  22
  23 include "common/ascii.ma".
  24
  25 (* ************************** *)
  26 (* DEFINIZIONE ASCII MINIMALE *)
  27 (* ************************** *)
  28
  29 ndefinition ascii_destruct_aux ≝
  30 Πc1,c2.ΠP:Prop.c1 = c2 →
  31  match eq_ascii c1 c2 with [ true ⇒ P → P | false ⇒ P ].
  32
  33 nlemma ascii_destruct : ascii_destruct_aux.
  34  #c1; #c2; #P; #H;
  35  nrewrite < H;
  36  nelim c1;
  37  nnormalize;
  38  napply (λx.x).
  39 nqed.