title: Y and H transforms
text: # Y and H transforms
  
  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) $Y_ν$ of order ν and the Struve function $H_ν$ of the same order.
  
  For a given function f(r), the Y-transform of order ν is given by
  
      $F(k)=\int _{0}^{\infty }f(r)Y_{\nu }(kr){\sqrt {kr}}\,dr$
  
  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
  
      $f(r)=\int _{0}^{\infty }F(k)\mathbf {H} _{\nu }(kr){\sqrt {kr}}\,dk$
  
  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).
  
  