Difference equations Differential-algebraic equations Symmetry (Mathematics) Algebraic aspects (differential-algebraic, hypertranscendence, group-theoretical) Axiomatics, foundations Classical differential geometry Curves in Euclidean space Difference and functional equations Difference equations, scaling ($q$-differences) Differential equations in the complex domain Differential geometry Dynamical systems and ergodic theory Finite-dimensional Hamiltonian, Lagrangian, contact, and nonholonomic systems General theory of group and pseudogroup actions General theory, relations with symplectic geometry and topology General topics Geometric theory, characteristics, transformations Lie algebras and Lie superalgebras Lie algebras of linear algebraic groups Mechanics of particles and systems Nonassociative rings and algebras Noncompact transformation groups Ordinary differential equations Partial differential equations Representations of solutions Solutions in closed form Topological groups, Lie groups