MBPAPPE
ω = g⁻¹ dg
ω = g⁻¹ dg
Riemann
f(z) = u(x, y) + i v(x, y)

z = x + i y, u(x, y) v(x, y)

∂u/∂x = ∂v/∂y
∂u/∂y = -∂v/∂x

f(z)