Fourier-Bessel series (source code)

= Fourier-Bessel series
{wiki=Fourier–Bessel_series}

Completeness: https://math.stackexchange.com/questions/2192665/is-this-set-of-bessel-functions-a-basis-for-all-c10-a-functions TODO

This is the <Bessel function> analogue to <fourier basis is complete for l2>.