Harmonic analysis 109 Mathematics 32 Fourier analysis 18 Differential equations, Partial 14 Functional analysis 13 Electric engineering 8 Operator theory 8 Topological groups 8 Differentiable dynamical systems 6 Electric power systems 6 Electromagnetic theory 6 Engineering mathematics 6 Fourier transformations 6 Global analysis (Mathematics) 6 Global differential geometry 6 Group theory 6 Harmonics (Electric waves) 6 Transformations (Mathematics) 6 Distribution (Probability theory) 5 Functions of complex variables 5 Lie groups 5 Mathematical optimization 5 Functions, Special 4 Functional equations 3 Geometry 3 Mathematical physics 3 Wavelets (Mathematics) 3 Algebra 2 Algorithms 2 Antennas (Electronics) 2