Has anyone used this before? Literature is limited and it may be key for reduction of some EM field equations I am developing in my masters. If I am correct the idea is to reduce Bessel functions across two offset cylindrical coordinate systems to a singular system. Correct if I am wrong and let me know if I could follow up with some further questions at some point.
https://www.wikiwaves.org/index.php/Graf%27s_Addition_Theorem
https://dlmf.nist.gov/10.23
