English
Conjugation commutes with the derivative form: conj(θ₂'(z,τ)) = θ₂'(conj(z), -conj(τ)).
Русский
Сопряжение переставляет производную: conj(θ₂'(z,τ)) = θ₂'(conj(z), -conj(τ)).
LaTeX
$$$\overline{\theta_2'(z,\tau)} = \theta_2'(\overline{z}, -\overline{\tau})$$$
Lean4
theorem jacobiTheta₂'_add_right (z τ : ℂ) : jacobiTheta₂' z (τ + 2) = jacobiTheta₂' z τ :=
by
refine tsum_congr (fun n ↦ ?_)
simp_rw [jacobiTheta₂'_term, jacobiTheta₂_term, Complex.exp_add]
suffices cexp (π * I * n ^ 2 * 2 : ℂ) = 1 by rw [mul_add, Complex.exp_add, this, mul_one]
rw [(by push_cast; ring : (π * I * n ^ 2 * 2 : ℂ) = (n ^ 2 :) * (2 * π * I)), exp_int_mul, exp_two_pi_mul_I, one_zpow]