Discrete Bessel and Mathieu Functions

Authors

Kenan Uriostegui, Institute of Physical Sciences, National Autonomous University of Me ́xico, Morelos 62251, Me ́xicoFollow
Kurt Bernardo Wolf, Institute of Physical Sciences, National Autonomous University of Me ́xico, Morelos 62251, Me ́xicoFollow

Author Country (or Countries)

Me ́xico

Abstract

The two-dimensional Helmholtz equation separates in elliptic coordinates based on two distinct foci, a limit case of which includes polar coordinate systems when the two foci coalesce. This equation is invariant under the Euclidean group of translations and orthogonal transformations; we replace the latter by the discrete dihedral group of N discrete rotations and reflections. The separation of variables in polar and elliptic coordinates is then used to define discrete Bessel and Mathieu functions, as approximants to the well-known continuous Bessel and Mathieu functions, as N-point Fourier transforms approximate the Fourier transform over the circle, with integrals replaced by finite sums. We find that these ‘discrete’ functions approximate the numerical values of their continuous counterparts very closely and preserve some key special function relations.

Digital Object Identifier (DOI)

http://dx.doi.org/10.18576/amis/150308

Recommended Citation

Uriostegui, Kenan and Bernardo Wolf, Kurt (2021) "Discrete Bessel and Mathieu Functions," Applied Mathematics & Information Sciences: Vol. 15: Iss. 3, Article 8.
DOI: http://dx.doi.org/10.18576/amis/150308
Available at: https://digitalcommons.aaru.edu.jo/amis/vol15/iss3/8