# 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:
 moebius-inversion× 39 For questions related to Moebius inversion and its applications. moebius-transformation× 39 For questions about the geometry, complex-analytic, and group-theoretic properties of the Möbius transformations (linear fractional transformations) $z \mapsto \frac{az + b}{cz + d}$ of the complex pl… perfect-numbers× 38 Questions about or involving perfect numbers which are positive integers that are equal to the sum of their proper positive divisors. mental-arithmetic× 38 Mental arithmetic comprises arithmetical calculations using only the human brain, with no help from calculators, computers, or pen and paper. least-common-multiple× 38 For questions about the least common multiple of a collection of numbers (or more generally, elements of a commutative ring). rationality-testing× 38 For questions on determining whether a number is rational, and related problems. If applicable, use this tag instead of (rational-numbers) and (irrational-numbers). Consider adding a tag (radicals) or… torsion-groups× 38 For questions about torsion groups and their properties. A torsion group is a group in which every element has finite order. distribution-tails× 38 finite-automata× 38 gauss-sums× 38 For questions on Gauss sums, a particular kind of finite sum of roots of unity. group-extensions× 38 indeterminate-forms× 38 If the expression obtained after any substitution during limit analysis does not give enough information to determine the original limit, it is known as an indeterminate form. vector-lattices× 38 For questions about vector lattices (aka. Riesz spaces; a type of vector space equipped with a partial order), Banach lattices and similar topics. cauchy-principal-value× 37 Computation of Cauchy principal values of integrals. May be tied in with contour integration, but should be separate from definite-integrals. stable-homotopy-theory× 37 ricci-flow× 37 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… klein-bottle× 37 a non-orientable surface. It was first described in 1882 by the German mathematician Felix Klein. kolmogorov-complexity× 36 Kolmogorov complexity concerns the size of the shortest program that generates a given string. transfinite-recursion× 36 Questions dealing with set-theoretic functions defined by transfinite recursion. topological-graph-theory× 36 For questions about topological graphs, flows, representation, planar, and book embeddings, geometric graphs, crossing numbers, coloring graphs, and other topics in topological graph theory. probabilistic-method× 35 Probabilistic methods prove existence results in a nonconstructive fashion, by showing the chance of randomly selecting a solution is greater than zero. profinite-groups× 35 For questions regarding profinite groups and their properties. l-functions× 35 meromorphic functions on $\mathbb{C}$ that are used extensively in number theory platonic-solids× 35 a regular, convex polyhedron with congruent faces of regular polygons and the same number of faces meeting at each vertex. music-theory× 35 fractional-part× 35 For questions related to the fractional part of a number. galois-cohomology× 34 manifolds-with-boundary× 34 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 … real-algebraic-geometry× 34 social-choice-theory× 33 For questions regarding the formal analysis of collective decision problems. nonclassical-logic× 33 For questions about three-valued logic and other non-classical logics. Please use the more specific tags 'modal-logic' and 'fuzzy-logic' instead of this tag if they apply. octave× 33 For questions about Octave, a high-level interpreted language for numerical computations. percolation× 33 Percolation theory describes the behavior of connected clusters in a random graph. integral-dependence× 33 cellular-automata× 33 chaotic-systems× 33