Mathematical physics 451 Physics 51 Mathematics 38 Differential equations, Partial 18 Quantum theory 16 Engineering mathematics 14 Mathematical Physics 11 Data processing 9 Mathematical analysis 9 Differential equations 8 Group theory 8 Quantum field theory 8 Geometry, Differential 7 SCIENCE / Mathematical Physics 7 Space and time 7 Matrices 6 Operator theory 6 String models 6 Green's functions 5 Integral equations 5 Nonlinear theories 5 Numerical analysis 5 Quantum groups 5 Boundary value problems 4 Congresses 4 General relativity (Physics) 4 Numerical solutions 4 Physicists 4 Relativity (Physics) 4 Superstring theories 4