# 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:
 greens-function× 127 for questions about a Green's function which is the impulse response of an inhomogeneous differential equation defined on a domain, with specified initial conditions or boundary conditions… idempotents× 127 For questions about elements which satisfy $x\cdot x=x$ where $\cdot$ is a composition law. matroids× 126 a common generalization of linearly independent sets and independent sets in graphs. Among other applications, they are exactly the simplical complexes in which the greedy algorithm outpu… regression-analysis× 125 for questions about regression analysis. In statistical modeling, regression analysis is a statistical process for estimating the relationships among variables. It includes many techniques… ricci-flow× 124 The Ricci flow on a Riemannian manifold $(M,g)$ is determined by the geometric evolution equation $\partial_t g_{ij} = -2R_{ij}$ where $R_{ij}$ is the Ricci curvature. The Ricci flow is the main ingre… quantum-field-theory× 123 In mathematical physics, constructive quantum field theory is the field whose objective is to establish existence theorems for models of quantum field theory. (Def: http://en.m.wikipedia.org/wiki/Co… perfect-numbers× 122 Questions about or involving perfect numbers which are positive integers that are equal to the sum of their proper positive divisors. symbolic-computation× 122 Numeric computation usually uses floating point numbers. Symbolic computations use symbols, and can give exact answers, such as $\sum_{n=1}^\infty \frac{1}{n^2} = \frac{\pi^2}{6}$. Mathematica, Maple… ordered-fields× 121 fields which have an additional structure, a linear order compatible with the field structure. This tag is for questions regarding ordered fields and their properties, as well proof… maximum-likelihood× 121 For questions that use the method of maximum likelihood for estimating the parameters of a statistical model with given data. chain-rule× 121 For questions involving the chain rule in analysis. additive-combinatorics× 120 about giving combinatorial estimates of addition and subtraction operations on Abelian groups or other algebraic objects. Key words: sum set estimates, inverse theorems, grap… big-picture× 120 Questions to get the "big picture" about a subject. grassmannian× 120 In mathematics, the Grassmannian $\mathbf{Gr}(r, V)$ is a space which parameterizes all linear subspaces of a vector space $V$ of given dimension $r$. higher-category-theory× 119 the part of category theory at a higher order, which means that some equalities are replaced by explicit arrows in order to be able to explicitly study the st… project-euler× 119 a series of challenging mathematical/computer programming problems. Please see the site and rules before posting. parametrization× 118 formal-systems× 118 broadly defined as any well-defined system of abstract thought based on the model of mathematics. (Def: http://en.m.wikipedia.org/wiki/Formal_system) uniform-spaces× 118 In the mathematical field of topology, a uniform space is a set with a uniform structure. (Def: http://en.m.wikipedia.org/wiki/Uniform_space) root-systems× 117 For questions involving abstract root systems, their associated Weyl groups and Dynkin diagrams, as well as their applications to Lie theory, graph theory, or other related fields. poissons-equation× 117 a partial differential equation of elliptic type with broad utility in electrostatics, mechanical engineering and theoretical physics. (Def: http://en.m.wikiped… injective-module× 117 injective if $\hom_{R}({-},I)$ is exact. The notion of injective modules is dual to the notion of a projective module. In homological algebra injective modules are used… levy-processes× 116 Question related to Lévy processes, i.e. stochastically continuous processes with independent, stationary increments. quadrilateral× 116 For questions about general quadrilaterals (including parallelograms, trapezoids, rhombi) and their properties. clustering× 116 grouping (partitioning) a set of objects so that items in the same group are more similar to each other than to items in different groups, where the notion of similarity may be variously… computational-algebra× 116 an area of algebra that seeks efficient algorithms to answer fundamental problems concerning basic algebraic objects (groups, rings, fields, etc.). For questions about generic… uniform-integrability× 116 For questions about families of uniformly integrable random variables. Use the tags [tag: measure-theory] or [tag: probablity-theory]. kahler-manifolds× 115 A complex manifold with a Hermitian metric is called a Kähler manifold if the (1,1) form that gives its Hermitian metric is a closed differential form. invariance× 114 called invariant if, given some steps that alter the object, always remains, no matter what steps are used in what order. decision-theory× 114 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. spectral-sequences× 113 (STUB) A method of computing homology groups by taking a sequence of approximations. Particularly useful in algebraic topology. pseudoinverse× 112 The operator which best approximates a solution to a linear system with a singular (non-invertible) matrix.: e.g., the Moore-Penrose pseudoinverse. Use when a question concerns a matrix that is probab… least-common-multiple× 111 For questions about the least common multiple of a collection of numbers (or more generally, elements of a commutative ring). cauchy-integral-formula× 111 In mathematics, Cauchy's integral formula, named after Augustin-Louis Cauchy, is a central statement in complex analysis. It expresses the fact that a holomorphic function defined on a disk is complet… coherent-sheaves× 110 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… inverse-function× 109 For questions regarding an inverse function as the dominant topic of the post, or for questions requesting guidance on finding the inverse function for a particular function.