## Subjects

The main purpose of the classification of items in the mathematical literature using the Mathematics Subject Classification scheme is to help users find the items of present or potential interest to them as readily as possible. The MSC is a hierarchical scheme, with three levels of structure. A classification can be two, three or five digits long, depending on how many levels of the classification scheme are used. The first level representing the main mathematical disciplines is labeled by a two digit number, the second representing specific areas is labeled by a letter (or a hyphen), and the third level for specific kind of mathematical object or a well-known problem or research area is labeled by another two digit number.

- 00-XX General
- 01-XX History and biography
- 03-XX Mathematical logic and foundations
- 05-XX Combinatorics
- 06-XX Order, lattices, ordered algebraic structures
- 08-XX General algebraic systems
- 11-XX Number theory
- 12-XX Field theory and polynomials
- 13-XX Commutative algebra
- 14-XX Algebraic geometry
- 15-XX Linear and multilinear algebra; matrix theory
- 16-XX Associative rings and algebras
- 17-XX Nonassociative rings and algebras
- 18-XX Category theory; homological algebra
- 19-XX $K$-theory
- 20-XX Group theory and generalizations
- 22-XX Topological groups, Lie groups
- 26-XX Real functions
- 28-XX Measure and integration
- 30-XX Functions of a complex variable
- 31-XX Potential theory
- 32-XX Several complex variables and analytic spaces
- 33-XX Special functions ( deals with the properties of functions as functions)
- 34-XX Ordinary differential equations
- 35-XX Partial differential equations
- 37-XX Dynamical systems and ergodic theory
- 39-XX Difference and functional equations
- 40-XX Sequences, series, summability
- 41-XX Approximations and expansions
- 42-XX Harmonic analysis on Euclidean spaces
- 43-XX Abstract harmonic analysis
- 44-XX Integral transforms, operational calculus

- 45-XX Integral equations
- 46-XX Functional analysis
- 47-XX Operator theory
- 49-XX Calculus of variations and optimal control; optimization
- 51-XX Geometry
- 52-XX Convex and discrete geometry
- 53-XX Differential geometry
- 54-XX General topology
- 55-XX Algebraic topology
- 57-XX Manifolds and cell complexes
- 58-XX Global analysis, analysis on manifolds
- 60-XX Probability theory and stochastic processes
- 62-XX Statistics
- 65-XX Numerical analysis
- 68-XX Computer science
- 70-XX Mechanics of particles and systems
- 74-XX Mechanics of deformable solids
- 76-XX Fluid mechanics
- 78-XX Optics, electromagnetic theory
- 80-XX Classical thermodynamics, heat transfer
- 81-XX Quantum theory
- 82-XX Statistical mechanics, structure of matter
- 83-XX Relativity and gravitational theory
- 85-XX Astronomy and astrophysics
- 86-XX Geophysics
- 90-XX Operations research, mathematical programming
- 91-XX Game theory, economics, social and behavioral sciences
- 92-XX Biology and other natural sciences
- 93-XX Systems theory; control
- 94-XX Information and communication, circuits
- 97-XX Mathematics education