Bessel functions Boundary conditions 6 Boundary value problems 6 Mathematical models 6 Theorem proving 6 Eigenvalues and eigenfunctions 4 Integral equations 4 Nonlinear boundary conditions 4 Problem solving 4 Sobolev trace embedding 4 Approximation theory 2 Atomic physics 2 Bessel beam 2 Calculations 2 Casimir energy 2 Cauchy theorem 2 Chaos theory 2 Concentric cylinder 2 Coulomb gauge 2 Differential equations 2 Dirac delta 2 Electromagnetic fields 2 Electron energy levels 2 Euclidean space 2 Gages 2 Green's function 2 Hankel transforms 2 Laser beams 2 Magnetic contribution 2 Mathematical transformations 2