Tags
A tag is a keyword or label that categorizes your question with other, similar questions.
Symplectic geometry is a branch of differential geometry and differential topology which studies symplectic manifolds; that is, differentiable manifolds equipped with a closed, nondegenerate 2-form.
1282 questions
Seemingly flawless arguments are often presented to prove obvious fallacies (such as 0=1). This is the appropriate tag to use when asking "Where is the proof wrong?" about proofs of such obvious fallacies.
1281 questions
For question about the concept of dual, either in the sense of vector spaces, topological group or dual problems.
1280 questions
For questions related to orthonormality. A set of vectors in an inner product space is called orthonormal if each vector is a unit vector, and vectors are pairwise orthogonal.
1275 questions
This tag is for questions about the foundations of mathematics, and the formalization of mathematical concepts in foundational theories (e.g. set theory, category theory, and type theory).
1261 questions
Rewriting rational function in the form of partial fractions is often useful when calculating integrals.
1254 questions
Regular languages are formal languages which are recognized by a finite automaton. It is equivalently the languages which are expressible as a regular expression. In addition to these two, there are several other equivalent definitions.
1253 questions
Questions about characteristic functions, of a set (which gives $1$ if the element is on the set and $0$ otherwise) or of a random variable (its Fourier transform). Do not use this tag if you are asking about the method of characteristics in PDE or the characteristic polynomial in linear algebra.
1252 questions
For questions on the exterior algebra, and related concepts such as the wedge product, the tensor algebra and differential forms.
1248 questions
Rational functions are ratios of two polynomials, for example $(x+5)/(x^2+3)$.
1246 questions
The properties of the Laplace differential operator, denoted $\Delta$ or $\nabla^2$, and defined as the divergence of the gradient. For Laplace equation, see (harmonic-functions)
1243 questions
For questions related to hyperbolic functions: $\sinh$, $\cosh$, $\tanh$, and so on.
1243 questions
For questions about decimal expansion, both practical and theoretical.
1243 questions
In mathematics, a monotonic function (or monotone function) is a function between ordered sets that preserves or reverses the given order. This concept first arose in calculus, and was later generalized to the more abstract setting of order theory. This tag may also include questions about applications or consequences of monotonicity, such as convergence, optimization, or inequalities.
1235 questions
For questions about fiber bundle, which is a space that is locally a product space, but globally may have a different topological structure.
1233 questions
Combinatorial proofs of identities use double counting and combinatorial characterizations of binomial coefficients, powers, factorials etc. They avoid complicated algebraic manipulations.
1225 questions
The study of computer algorithms which admit geometric descriptions, and geometric problems arising in association with such algorithms. The two major classes of problems are (a) efficient design of algorithms and data classes using geometric concepts and (b) representation and modelling of curves and surfaces.
1221 questions
For questions on fractals, which are irregular, rough, or "fractured" sets that often possess self-similar structure.
1220 questions
For questions on knot theory, the study of mathematical knots and their properties.
1214 questions
For help with mathematical questions arising from software such as Maple, MATLAB, Mathcad, Pari/GP, R, and the WolframAlpha website, etc. Consider posting questions about Mathematica at the Mathematica StackExchange instead. For GAP, SAGE, and MAGMA, one might use tags (computer-algebra-systems), (gap), (sage), (magma-cas).
1210 questions
Relating to a symmetric $n\times n $ real matrix $(M)$ such that the scalar $x^TMx\ge 0\ \forall x\in \Bbb{R}^n\backslash \{0\}$
1203 questions
For questions about the composition of functions and relations.
1202 questions
For questions about algebraic geometry that focus on affine space. For affine mappings in linear algebra (i.e. linear mappings plus translations), please use the linear-algebra tag or another appropriate tag.
1202 questions
A is an expression obtained through an iterative process of representing a number as the sum of its integer part and the reciprocal of another number.
1191 questions
This tag is for question about changing basis of a finite dimensional vector space. For example, how does the representation of a vector, or a matrix change with the change of basis. Please don't use this tag on its own, it is better to add a more general tag which is relevant to your question, e.g. [linear-algebra] or [matrices] for better visibility.
1175 questions
A bilinear form over an $F$-vector space $V$ is a mapping $B:V\times V\to F$ that is linear in each of its arguments, when the other argument is held fixed.
1162 questions
A geodesic is a generalisation of the notion of a straight line to curved spaces, and can be sometimes be thought of as the locally shortest or extremal path between points.
1157 questions
A conformal structure is one that captures the idea of angles, but not lengths. Conformal geometry is the study of geometries with conformal structures, with special focus on transformations that preserves the angles (while possibly changing lengths). Examples of conformal transformations include the Mercator projection from cartography, and the Möbius transformations of the Riemann sphere.
1155 questions
For questions about adjoint operators in inner product spaces. For adjoint functors from category theory, use the tag (adjoint-functors).
1153 questions
For questions about discrete optimization, which is a branch of optimization with discrete variables, opposed to continuous optimization in applied mathematics and computer science.
1151 questions
A von Neumann algebra is a unital *-subalgebra of the algebra of bounded operators on a Hilbert space, closed in the weak operator topology. Also called a $W^*$-algebra, and may be regarded as a non-commutative generalization of $L^\infty$ space. These algebras are extensively used in knot theory, non-commutative geometry, and quantum field theory.
1137 questions
An isometry is a map between metric spaces that preserves the distance. This tag is for questions relating to isometries.
1136 questions
In mathematics, a line integral is an integral where the function to be integrated is evaluated along a curve. The terms path integral, curve integral, and curvilinear integral are also used.
1126 questions