Fourier analysis Mathematics 68 Functional analysis 18 Harmonic analysis 18 Differential equations, Partial 15 Signal processing 14 Wavelets (Mathematics) 14 Image processing 11 Engineering mathematics 8 Fourier transformations 8 Global analysis (Mathematics) 8 Distribution (Probability theory) 7 Computer science 6 Data processing 6 Engineering 6 Functions of complex variables 6 Functions, Special 6 Numerical analysis 5 Operator theory 5 Differential equations 4 Nanoelectronics 4 Nanophotonics 4 Number theory 4 System analysis 4 Approximation theory 3 Biomedical engineering 3 Boundary value problems 3 Computer vision 3 Differentiable dynamical systems 3 Group theory 3