9 lines
260 B
Text
9 lines
260 B
Text
import data.examples.vector
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open nat vector
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set_option pp.implicit true
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set_option pp.notation false
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definition diag {A : Type*} : Π {n}, vector (vector A n) n → vector A n,
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diag nil := nil,
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diag ((a :: va) :: vs) := a :: diag (map tail vs)
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