English
For p > 0 and x ∈ ℝ, there is an alternative expression: ‖(x : AddCircle p)‖ = p · | p⁻¹ x − round(p⁻¹ x) |.
Русский
При p > 0 существует альтернативное выражение: ‖(x : AddCircle p)‖ = p · | p⁻¹ x − round(p⁻¹ x) |.
LaTeX
$$$$\\| (x : \\mathrm{AddCircle}(p)) \\| = p \\cdot \\left| p^{-1} x - \\operatorname{round}(p^{-1} x) \\right|.$$$$
Lean4
theorem norm_eq' (hp : 0 < p) {x : ℝ} : ‖(x : AddCircle p)‖ = p * |p⁻¹ * x - round (p⁻¹ * x)| :=
by
conv_rhs =>
congr
rw [← abs_eq_self.mpr hp.le]
rw [← abs_mul, mul_sub, mul_inv_cancel_left₀ hp.ne.symm, norm_eq, mul_comm p]