In mathematics, the Y transforms and H transforms are complementary pairs of integral transforms involving, respectively, the Neumann function (Bessel function of the second kind) Yν of order ν and the Struve function Hν of the same order.
For a given function f(r), the Y-transform of order ν is given by The inverse of above is the H-transform of the same order; for a given function F(k), the H-transform of order ν is given by These transforms are closely related to the Hankel transform, as both involve Bessel functions.
In problems of mathematical physics and applied mathematics, the Hankel, Y, H transforms all may appear in problems having axial symmetry.
Hankel transforms are however much more commonly seen due to their connection with the 2-dimensional Fourier transform.
The Y, H transforms appear in situations with singular behaviour on the axis of symmetry (Rooney).