Hankel

The late Erwin Klusmann, New Salem, N.D., and Wayne Hankel, Fargo, were the Hall of Fame inductees.

Hankel doesn't mention the author of the theorem.

See also the subsection on Hankel functions below.

Stokes set the theorem as a question on the 1854 Smith's Prize exam, which led to the result bearing his name, even though it was actually first published by Hermann Hankel in 1861.

The Bessel function of the second kind then can be thought to naturally appear as the imaginary part of the Hankel functions.

The Hankel functions are used to express outward- and inward-propagating cylindrical wave solutions of the cylindrical wave equation, respectively (or vice versa, depending on the sign convention for the frequency ).

The importance of Hankel functions of the first and second kind lies more in theoretical development rather than in application.