English
For integer j, toCircle(j mod N) equals exp(2π i j / N).
Русский
Для целого j отображение toCircle(j mod N) равно exp(2π i j / N).
LaTeX
$$$\\forall j ∈ \\mathbb{Z},\\; toCircle(j \\bmod N) = \\exp\\left(2\\pi i \\frac{j}{N}\\right)$$$
Lean4
/-- `ZMod.toCircle` as an `AddChar` into `rootsOfUnity n Circle`. -/
noncomputable def rootsOfUnityAddChar (n : ℕ) [NeZero n] : AddChar (ZMod n) (rootsOfUnity n Circle)
where
toFun x := ⟨toUnits (ZMod.toCircle x), by ext; simp [← AddChar.map_nsmul_eq_pow]⟩
map_zero_eq_one' := by simp
map_add_eq_mul' _ _ := by ext; simp [AddChar.map_add_eq_mul]