theorem
proved
term proof
winding_integral_simple_pole
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formal statement (Lean)
313theorem winding_integral_simple_pole (c w : ℂ) (R : ℝ) (hw : w ∈ Metric.ball c R) :
314 (∮ z in C(c, R), (z - w)⁻¹) = 2 * ↑π * Complex.I :=
proof body
Term-mode proof.
315 circleIntegral.integral_sub_inv_of_mem_ball hw
316
317/-- Cauchy–Goursat for the circle: if `f` is holomorphic on the closed disk
318(possibly off a countable set), the contour integral vanishes. -/