2015-01-13 22:38:25 +00:00
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import data.vector
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open nat vector prod
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variables {A B : Type}
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2015-02-26 00:20:44 +00:00
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definition unzip : Π {n : nat}, vector (A × B) n → vector A n × vector B n
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| unzip nil := (nil, nil)
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| unzip ((a, b) :: v) :=
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2015-01-13 22:38:25 +00:00
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match unzip v with
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(va, vb) := (a :: va, b :: vb)
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end
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example : unzip ((1, 20) :: (2, 30) :: nil) = (1 :: 2 :: nil, 20 :: 30 :: nil) :=
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rfl
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