Functional analysis-- Mathematics 180 Functional analysis 103 Operational calculus-- Functional analysis-- Mathematics 100 Special functions-- Analysis-- Mathematics 58 Mathematics 52 Functional Analysis 17 Functions of real variables 9 Measure theory 9 MATHEMATICS / Functional Analysis 7 Operator theory 7 Analysis 6 Functions 6 Calculus 4 Functional analysis -- Instructional exposition (textbooks, tutorial papers, etc.) 4 Functions of complex variables 4 Theory of distributions (Functional analysis) 4 Topology 4 Approximation theory 3 Differential equations, Partial 3 Functions of complex variables-- Analysis-- Mathematics 3 Mathematical optimization 3 Measure and integration -- Instructional exposition (textbooks, tutorial papers, etc.) 3 Metric spaces 3 Nonlinear functional analysis 3 Operational calculus; Functional analysis; Mathematics 3 Special functions; Analysis; Mathematics 3 Approximations and expansions 2 Computational Biology 2 Data processing 2 Engineering mathematics 2