# 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:
 calendar-computations× 64 for questions about combinatorial and computational issues with regards to calendar systems. A typical, well-known mathematical result in this direction is John Conway's Doomsday Algorithm… borel-cantelli-lemmas× 64 For questions involving the Borel-Cantelli Lemma or the second Borel-Cantelli Lemma. Use this tag along with (probability-theory), (real-analysis) or (measure-theory) groupoids× 64 A groupoid (in the sense of category theory) is a small category in which every morphism is an isomorphism. Groupoids arise throughout mathematics, e.g. in guise of fundamental groupoids in the theory… direct-product× 64 For questions about the direct product of groups, rings, fields or categories. Use (group-theory), (ring-theory), (field-theory) or (category-theory). linear-approximation× 64 For questions about linear approximations, $f(x) \approx f(a)+f'(a)(x-a)$ for $x$ around $a$. toric-geometry× 64 linear-groups× 63 a group $G$ whose elements are invertible $n \times n$ matrices over a field $F$. satisfiability× 63 For questions on the subject of "satisfiability", that is, whether there exists an interpretation/model in which a given (logical) formula is true. gamma-distribution× 63 galois-representations× 63 automorphic-forms× 63 a generalization of the idea of periodic functions in Euclidean space to general topological groups. beta-function× 63 For questions about Beta function, a special function closely related to Gamma. It is advisable to also use [special-functions] tag with this one. chemistry× 62 Questions related to mathematical chemistry which include application of mathematics to problems in chemistry and the development of mathematical methods suitable for such applications and for the for… fuzzy-logic× 62 a form of many-valued logic that deals with approximate, rather than fixed and exact reasoning. (Def: http://en.m.wikipedia.org/wiki/Fuzzy_logic) greens-theorem× 62 faq× 62 meant for questions which are generalized forms of questions which get asked frequently. See tag details for more information. spherical-trigonometry× 62 perfect-numbers× 62 Questions about or involving perfect numbers which are positive integers that are equal to the sum of their proper positive divisors. orientation× 61 For question regarding the notion of orientation both in topology and in global analysis. classifying-spaces× 61 A classifying space $BG$ of a topological group $G$ is the quotient of a weakly contractible space $EG$ by a free action of $G$. When $G$ is a discrete group $BG$ has homotopy type of $K(G,1)$ and (co… blowup× 61 A technique in geometry (especially algebraic and differential, and by extension to study of pseudo-differential operators) for resolution of singularities. Not to be confused with the formation of si… goldbachs-conjecture× 60 For questions about Goldbach's conjecture: every even integer greater than two is the sum of two primes. gauge-theory× 60 Connections on principal bundles, gauge groups, Yang-Mills connections, (anti-)self-dual connections, stability of vector bundles, Donaldson invariants, the Seiberg-Witten equations and invariants, th… k-theory× 59 the study of invariants of large matrices, in a suitable sense. It has many variations: (algebraic-k-theory), (topological-k-theory), or in the study of (operator-algebras). metric-geometry× 59 The study of geometry of manifolds without appealing to differential calculus. It includes studies of length spaces, Alexandrov spaces, and CAT(k) spaces. The techniques are often applicable to Rieman… mathematicians× 59 Questions about mathematicians and their lives. popular-math× 58 Question on bits and pieces of mathematics that show up in popular media (TV, movies, comics, etc.) product-space× 58 For questions about the structure of product space, in the context of topology or measure theory for example. Use other tags to indicate the context. quadratic-variation× 57 Questions on quadratic variations of stochastic processes. (Not to be confused with functions of bounded variation.) quantum-computation× 57 extrapolation× 57 For question on extrapolation, the process of estimating, beyond the original observation interval. deformation-theory× 57 The study of how mathematical objects (complex manifolds, associative algebras, Lie algebras) can be deformed into similar mathematical objects, at least infinitesimally. symplectic-linear-algebra× 57 Questions about vector spaces equipped with a symplectic form, a non-degenerate, skew-symmetric bilinear form. coxeter-groups× 56 For questions about Coxeter groups, an abstract group that admits a formal description in terms of reflections. etale-cohomology× 56 manifolds-with-boundary× 56 typically defined to be without boundaries (every point has a neighbourhood homeomorphic to an Euclidean open disc). Use this tag for the manifolds with boundaries, as well as manifolds …