Digital Library of Mathematical Functions
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30 Spheroidal Wave FunctionsProperties

§30.6 Functions of Complex Argument

The solutions

of (30.2.1) with \mu=m and \lambda=\mathop{\lambda^{{m}}_{{n}}\/}\nolimits\!\left(\gamma^{2}\right) are real when z\in(1,\infty), and their principal values (§4.2(i)) are obtained by analytic continuation to \Complex\setminus(-\infty,1].