IdrisDoc: Control.Isomorphism.Fin

Control.Isomorphism.Fin

rotatedDown : Iso (Fin n) (Fin n)

Sends FZ to last, and FS x to x.

rotatedUp : Iso (Fin n) (Fin n)

Sends last to FZ and every other x to FS x.

strengthenLast : (n : Nat) -> strengthen last = Left last
strengthenLeft : (i : Fin (S n)) -> (prf : strengthen i = Left x) -> i = last
strengthenRight : (i : Fin (S n)) -> (prf : strengthen i = Right x) -> weaken x = i
strengthenWeaken : (n : Fin k) -> strengthen (weaken n) = Right n