Functional Analysis 95 Functional analysis Functions of complex variables Functions of a Complex Variable 79 Operator Theory 33 Operator theory 33 Several Complex Variables and Analytic Spaces 32 Differential Equations 26 Differential equations 26 Mathematical analysis 16 Abstract Harmonic Analysis 13 Harmonic analysis 13 Functions of real variables 10 Real Functions 10 Measure and Integration 9 Measure theory 9 Analysis 8 Approximation theory 8 Approximations and Expansions 8 Integral Transforms and Operational Calculus 8 Special Functions 8 Special functions 8 Fourier Analysis 7 Fourier analysis 7 Differential Geometry 6 Dynamical Systems 6 Dynamical systems 6 Geometry, Differential 6 Integral Equations 6 Integral equations 6