A function on an open U ⊂ ℂ that is holomorphic outside a discrete set of poles; equivalently a holomorphic map U → ℂ ∪ {∞} = ℙ¹.
A function on an open U ⊂ ℂ that is holomorphic outside a discrete set of poles; equivalently a holomorphic map U → ℂ ∪ {∞} = ℙ¹.