simp [encode, decode, Nat.fin_mod, FinDenumerable.decode_fin]
α : Type u_1
inst : Alphabet α
x : α
xs : List α
ih : decode (encode xs) = xs
⊢ decode (encode (x :: xs)) = x :: xs
α : Type u_1
inst : Alphabet α
x : α
xs : List α
ih : decode (encode xs) = xs
⊢ Option.get (Encodable.decode ((encode xs * Fintype.card α + Encodable.encode x) % Fintype.card α)) ⋯ ::
      decode ((encode xs * Fintype.card α + Encodable.encode x) / Fintype.card α) =
    x :: xs