matita/matita/tests/letrec.ma

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  17
  18 alias id "O" = "cic:/Coq/Init/Datatypes/nat.ind#xpointer(1/1/1)".
  19 alias id "S" = "cic:/Coq/Init/Datatypes/nat.ind#xpointer(1/1/2)".
  20 alias id "nat" = "cic:/Coq/Init/Datatypes/nat.ind#xpointer(1/1)".
  21
  22 let rec plus n m \def
  23  match n with
  24   [ O \Rightarrow m
  25   | (S x) \Rightarrow S (plus x m) ].