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