# 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:
 idempotents× 89 For questions about elements which satisfy $x\cdot x=x$ where $\cdot$ is a composition law. career-development× 88 Questions on mathematical career development. Consider whether your question is more appropriate for Academia Stack Exchange. sage× 88 For questions concerning Sage. Consider whether your question would be a better fit at [ask Sage](http://ask.sagemath.org/). levy-processes× 88 Question related to Lévy processes, i.e. stochastically continuous processes with independent, stationary increments. decision-theory× 87 For questions regarding formal decision problems. In contrast, questions involving strategic aspects (where the solution depends on the behavior of others) are discussed in game theory. hash-function× 87 For questions about hash functions: functions from a big set to a smaller one such that the same output $f(x_1)=f(x_2)$ for different input $x_1\ne x_2$ is unlikely, especially if $x_2$ differs from $… euler-lagrange-equation× 87 In calculus of variations, the Euler–Lagrange equation, Euler's equation, or Lagrange's equation, is a second-order partial differential equation whose solutions are the functions for which a given fu… grassmannian× 86 In mathematics, the Grassmannian$\mathbf{Gr}(r, V)$is a space which parameterizes all linear subspaces of a vector space$V$of given dimension$r$. classical-analysis× 86 spherical-harmonics× 86 Questions on spherical harmonics, a set of basis functions that satisfy an orthogonality relation over the sphere. quadrilateral× 86 For questions about general quadrilaterals (including parallelograms, trapezoids, rhombi) and their properties. research× 85 big-numbers× 85 For questions relating to the computation, estimation and properties of extremely large quantities that are not usually used in mainstream mathematics. higher-order-logic× 85 In mathematics and logic, a higher-order logic is a form of predicate logic that is distinguished from first-order logic by additional quantifiers and a stronger semantics. (Def: http://en.m.wikiped… graded-modules× 84 gaussian-integral× 84 For questions regarding the theory and evaluation of the Gaussian integral, also known as the Euler–Poisson integral . topological-k-theory× 83 a generalized cohomology theory, for which$K_0(X)$is the Grothendieck group of isomorphism classes of vector bundles over topological space$X$. See also (algebraic-k-theory)… universal-property× 82 independence× 82 publishing× 81 for questions about publishing mathematical content ceiling-function× 81 The function that maps a real number$x$to the smallest integer greater than or equal to$x$(which is often denoted$\lceil x\rceil$. See also (floor-function). combinatorial-designs× 80 For questions about Combinatorial design theory, a part of combinatorial mathematics that deals with the existence, construction and properties of systems of finite sets whose arrangements satisfy gen… geometric-series× 80 For questions about or involving geometric series, a series where successive terms have a common ratio. hodge-theory× 80 The study of relations between, one the one hand, the topology of a smooth manifold as encoded in the cohomology groups, and on the other, the set of solutions to the Laplace operator on differential … isometry× 80 a map between metric spaces that preserves the distance. This tag is for questions relating to isometries. invariance× 80 called invariant if, given some steps that alter the object, always remains, no matter what steps are used in what order. z-transform× 80 a discrete analogue to the Laplace transform, in that it maps a time domain signal into a representation in complex frequency plane. noncommutative-geometry× 79 a study of noncomutative algebras from geometrical point of view. The motivation of this approach is Gelfand representation theorem, which shows that every commutative C*-al… multiplicative-function× 79 In number theory, a multiplicative function is a function defined on positive integers such that f(ab)=f(a)f(b) for a,b coprime. E.g. Euler's totient function, sum of divisors and number of divisor… meta-math× 79 the term for the theory in which mathematics is formalized (often PA, ZFC or similar theories). Meta-mathematical statements are statements which are evaluated at the level of the meta-… division-algebras× 79 a vector spaces over a field$F$equipped with a bilinear product and a multiplicative neutral element$1$. All the non-zero elements of$D\$ have a multiplicative inverse. As… affine-schemes× 79 The spectrum of a commutative ring with unit is the set of prime ideals endowed with the Zariski topology. One can define a sheaf of rings on this space : to each Zariski-open set is assigned a commut… algorithmic-game-theory× 78 an area in the intersection of game theory and algorithm design, whose objective is to design algorithms in strategic environments. (Def: http://en.m.wikipedia.org/wiki/Al… complex-dynamics× 78 the study of dynamical systems of functions over complex numbers. coherent-sheaves× 78 In mathematics, especially in algebraic geometry and the theory of complex manifolds, coherent sheaves are a specific class of sheaves having particularly manageable properties closely linked to the g… model-categories× 78 categories with three distinguished classes of morphisms: the weak equivalences, the fibrations and the cofibrations. They provide a natural setting for (homotopy-theory) in an ar…