= Doubly connected domain
{title2=$|\pi_0(\widehat{\mathbb C}\setminus\Omega)|=2$}
A planar <domain> whose complement in the <Riemann sphere> has exactly two <connected components>. An <annulus> is the standard example. If neither complementary component is a single point, the domain is conformally equivalent to a circular <annulus> with finite positive <conformal modulus of an annulus>; punctured-disc and punctured-plane cases account for degenerate complementary components.
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