Mathematics 12 Number theory 10 Group theory 4 Probabilities 4 Calculus of variations 3 Difference equations 3 Differential equations 3 Geometry, Analytic 3 Politics and government 3 Algebra 2 Algebras, Linear 2 Analytic functions 2 Determinants 2 Economic aspects 2 Fourier series 2 Functional equations 2 History 2 Logic, Symbolic and mathematical 2 Matrices 2 Political aspects 2 Psychology 2 Riemann surfaces 2 Set theory 2 Surfaces 2 Topology 2 Agriculture 1 Algebraic functions 1 Algebraic logic 1 Alternative lifestyles 1 American poetry 1