# 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:
 pythagorean-triples× 165 Questions about Pythagorean triples, positive integer solutions to $a^2 + b^2 = c^2$. graph-isomorphism× 165 isomorphic if they have a function $f$ which provides an exact pairing of vertices in the two graphs such that for any adjacent vertices $u,v\in \{\mbox{set of vertices of }… network-flow× 164 For questions about networks that inhibit source and sink nodes and a notion of flow. localization× 164 For questions regarding the process, consequences, and stability of localizing algebraic structures such as rings, categories, and modules. Not for use with local topological spaces. quadratic-programming× 163 for questions on Quadratic Programming (QP). A QP problem is the problem of minimising or maximising a quadratic objective function subject to affine constraints. error-function× 163 for the error and complementary error functions (erf and erfc). These are special functions formed by taking definite integrals of the Gaussian/normal distribution function. sorting× 163 For questions about dividing groups of objects based on their properties. separation-axioms× 162 properties of topological space which, roughly speaking, say in what way two points, a point and a closed set, or two closed sets can be "separated". semidirect-product× 162 a construction in group theory generalizing the direct product. It arises as the structure of a group$G$with a normal subgroup$N$having a complement$N$. elliptic-integrals× 162 Questions on elliptic integrals, integrals that involve the square root of a cubic or quartic polynomial. principal-bundles× 162 a mathematical object which formalizes some of the essential features of the Cartesian product$X\times G$of a space$X$with a group$G$. golden-ratio× 161 Questions relating to the golden ratio$\varphi = \frac{1+\sqrt{5}}{2}$branch-cuts× 161 curve in the complex extending from a branch point of the function. solvable-groups× 161 For questions on solvable groups, their properties, and structure. bernoulli-numbers× 160 Questions on Bernoulli numbers, a special sequence of rational numbers that arise as the coefficients in the power series expansions of certain elementary functions. catalan-numbers× 159 For questions on Catalan numbers, a sequence of natural numbers that occur in various counting problems. positive-definite× 159 For questions regarding the positive-definiteness of matrices. newton-raphson× 159 for questions regarding the Newton–Raphson method. In numerical analysis the Newton–Raphson method is a method for finding successively better approximations to the roots (or zeroes) of a … diophantine-approximation× 158 For questions about approximating real numbers by rational numbers. optimal-control× 157 Optimal control theory, an extension of the calculus of variations, is a mathematical optimization method for deriving control policies. (Def: http://en.m.wikipedia.org/wiki/Optimal_control) homogeneous-equation× 157 called homogeneous if the following condition is satisfied: If$\phi(x)$is a solution, so is$c \phi(x)$, where c is an arbitrary (non-zero) constant. (Def: http:… monoidal-categories× 156 In mathematics, a monoidal category (or tensor category) is a category C equipped with a bifunctor ⊗ : C × C → C which is associative up to a natural isomorphism, and an object I which is both a lef… infinite-groups× 155 For questions about groups where the underlying set has infinite cardinality. quantum-groups× 155 In mathematics and theoretical physics, the term quantum group denotes various kinds of noncommutative algebra with additional structure. (Def: http://en.m.wikipedia.org/wiki/Quantum_group) article-writing× 155 Various aspects of writing mathematics such as style, notation, grammar, frequently used phrases and common mistakes. absolute-convergence× 155 for questions related to absolute convergence a series. riemann-hypothesis× 154 Questions on the Riemann hypothesis, a conjecture on the behavior of the complex zeros of the Riemann$\zeta$function. You might want to add the tag [riemann-zeta] to your question as well. reflection× 154 a transformation that fixes a line or plane or a more general subset. Reflections appear in geometry, linear algebra, complex analysis, differential equations, etc -- therefore, this ta… group-rings× 154 a ring constructed from a group$G$and ring$R$. A special case of this construction is group algebra, which occurs naturally in representation theory. variance× 154 For questions regarding the variance of a random variable in probability, as well as the variance of a list or data in statistics. infinitesimals× 153 For questions about infinitesimals, both in an intuitive sense as well as more rigorous settings (see also [nonstandard-analysis]). constants× 153 For questions about mathematical constants, that are "significantly interesting in some way". density-function× 153 For questions on using, finding, or otherwise relating to probability density functions (PDFs) wavelets× 151 For questions related to wavelets and wavelet theory graded-rings× 150 In mathematics, in particular abstract algebra, a graded ring is a ring that is a direct sum of abelian groups$R_i$such that$R_i R_j \subset R_{i+j}\$. (Def: http://en.m.wikipedia.org/wiki/Graded_ri… modal-logic× 150 Questions relating to deductions relating to the expressions "it is necessary that" and "it is possible that"