x y : ℝ
⊢ (∃ n, ↑x * I = ↑y * I + ↑n * (2 * ↑π * I)) ↔ ∃ m, x = y + ↑m * (2 * π)
x y : ℝ
⊢ ↑expMapCircle x = ↑expMapCircle y ↔ ∃ m, x = y + ↑m * (2 * π)
rw [Subtype.ext_iff, expMapCircle_apply, expMapCircle_apply, exp_eq_exp_iff_exists_int]
x y : ℝ
n : ℤ
⊢ ↑x * I = ↑y * I + ↑n * (2 * ↑π * I) ↔ x = y + ↑n * (2 * π)
x y : ℝ
⊢ (∃ n, ↑x * I = ↑y * I + ↑n * (2 * ↑π * I)) ↔ ∃ m, x = y + ↑m * (2 * π)
refine' exists_congr fun n => _
x y : ℝ
n : ℤ
⊢ ↑x = ↑y + ↑n * (2 * ↑π) ↔ x = y + ↑n * (2 * π)
x y : ℝ
n : ℤ
⊢ ↑x * I = ↑y * I + ↑n * (2 * ↑π * I) ↔ x = y + ↑n * (2 * π)
rw [← mul_assoc, ← add_mul, mul_left_inj' I_ne_zero]
no goals
x y : ℝ
n : ℤ
⊢ ↑x = ↑y + ↑n * (2 * ↑π) ↔ x = y + ↑n * (2 * π)
norm_cast