42XX 


Fourier analysis 

42Cxx 

Nontrigonometric Fourier 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.) 


42C15 
Series of general orthogonal functions, generalized Fourier expansions, nonorthogonal expansions 


42C20 
Rearrangements and other transformations of Fourier and other orthogonal series 


42C25 
Uniqueness and localization for orthogonal series 


42C30 
Completeness of sets of functions 


42C40 
Wavelets 


42C99 
None of the above, but in this section 