42Cxx Nontrigonometric harmonic analysis
- 42C05 Orthogonal functions and polynomials, general theory [See also 33C45, 33C50, 33D45]
- 42C10 Fourier series in special orthogonal functions (Legendre polynomials, Walsh functions, etc.) (2)
- 42C15 General harmonic expansions, frames (3)
- 42C20 Other transformations of harmonic type
- 42C25 Uniqueness and localization for orthogonal series (1)
- 42C30 Completeness of sets of functions (1)
- 42C40 Wavelets and other special systems (19)
- 42C99 None of the above, but in this section