# Tags

A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.

 Type to find tags:
 finite-fields× 281 a field with a finite number of elements. For each prime power $q^k$, there is a unique (up to isomorphism) finite field with $q^k$ elements. Up to isomorphism, these are the only … order-theory× 279 topological-groups× 273 a group $G$ together with a topology on the elements of $G$ such that the group operation and group inverse function are both continuous (with respect to the topology). schemes× 272 the geometrical study of solutions of algebraic systems of equations, not only over the real/complex numbers, but also over integer numbers (and more generally o… elliptic-pde× 272 Questions about partial differential equations of elliptic type. Often used in combination with the top-level tag ap.analysis-of-pdes. abstract-algebra× 271 etale-cohomology× 269 galois-representations× 268 stacks× 267 random-matrices× 264 Statistics of spectral properties of matrix-valued random variables. axiom-of-choice× 263 3-manifolds× 256 additive-combinatorics× 253 Questions on the subject additive combinatorics, also known as arithmetic combinatorics, such as questions on: additive bases, sum sets, inverse sum set theorems, sets with small doubling, Sidon sets,… derived-category× 252 For questions about the derived categories of various abelian categories and questions regarding the derived category construction itself. fields× 248 Fields as algebraic objects. For vector and tensor fields, use eg. [dg.differential-geometry]. For physical fields, use eg. [mp.mathematical-physics] or [quantum-field-theory]. modules× 247 For questions on modules over rings. quadratic-forms× 245 descriptive-set-theory× 245 the study of definable subsets of Polish spaces, where definable is taken to mean from the Borel or projective hierarchies. Other topics include infinite games and determinac… big-picture× 245 Questions designed to get an overview of a specific subject or body of results or to understand the relations among similar definitions, techniques or concepts appearing in different sub-fields of mat… singularity-theory× 244 matrix-analysis× 241 The study of the properties of real and complex matrices that are more close to analysis and operator theory. For instance: the properties of positive definite matrices, matrix inequalities, perturbat… commutative-rings× 239 quantum-groups× 237 Questions about algebraic structures known as quantum groups, and their categories of representations. Quasitriangular Hopf algebras and their Drinfel'd twists, triangular Hopf algebras, $C^\star$ qua… topos-theory× 237 projective-geometry× 235 intuition× 235 Questions asking for the intuition behind some definition, conjecture, proof etc. In other words, questions designed to improve or to acquire understanding on a conceptual or intuitive level, as oppos… von-neumann-algebras× 233 Subtag of [tag:oa.operator-algebras] for questions about von Neumann algebras, that is, weak operator topology closed, unital, *-subalgebras of bounded operators on a Hilbert space. noncommutative-algebra× 232 linear-programming× 231 the study of optimizing a linear function over a set of linear inequalities. The Simplex Method, Ellipsoid Method and Interior Point Method are popular algorithms to solve linea… noncommutative-geometry× 229 Noncommutative geometry in the sense of Connes and beyond: noncommutative algebras viewed as functions on a noncommutative space. algebraic-k-theory× 226 hopf-algebras× 221 a vector space $H$ over a field $k$ endowed with an associative product $\times:H\otimes_k H\to H$ and a coassociative coproduct $\Delta:H\to H\otimes_k H$ which is a morphism of alg… approximation-theory× 217 convex-optimization× 217 Optimization with convex constraints and convex objectives; notions related to convex optimization such as sub-gradients, normal cones, separating hyperplanes mathematics-education× 216 For questions in Mathematics Education as a scientific discipline. For more hands-on questions on teaching Mathematics, please use the tag teaching. There is also a Stack Exchange community http://mat… markov-chains× 215