Functional analysis Mathematics 138 Differential equations, Partial 54 Operator theory 41 Global analysis (Mathematics) 27 Mathematical optimization 27 Distribution (Probability theory) 21 Mathematical physics 20 Fourier analysis 18 Functions of complex variables 16 Algebra 15 Harmonic analysis 13 Differential equations 11 Engineering mathematics 9 Number theory 9 Differentiable dynamical systems 8 Functions, Special 8 Measure theory 8 Numerical analysis 8 Topology 8 Global analysis 7 Integral equations 7 Mathematical models 7 Potential theory (Mathematics) 7 Topological groups 7 Calculus of variations 6 Computer science 6 Discrete groups 6 Engineering 6 Functional equations 6