Tags
A tag is a keyword or label that categorizes your question with other, similar questions.
Use this tag for questions about (1) distributions of a sum of squares of independent standard normal random variables or (2) statistical hypothesis tests with such a sampling distribution if the null hypothesis is true.
434 questions
Use this tag for questions about quantum field theory in theoretical/mathematical physics. Quantum Field Theory is the theoretical framework describing the quantization of classical fields allowing a Lorentz-invariant formulation of quantum mechanics. Associate with [tag:mathematical-physics] if necessary.
433 questions
For questions related to Euler's constant $\gamma$, which is defined to be the limiting difference between the natural logarithm and the harmonic series.
433 questions
It is the study of smooth manifolds equipped with a non-degenerate metric tensor, not necessarily positive-definite (and hence a generalisation of [riemannian-geometry]). Included in this are metric tensors with index 1, called "Lorentzian", which are used to model spacetimes in (general-relativity).
431 questions
Use this tag for questions about the principle that a random variable that depends in a Lipschitz way on many independent variables (but not too much on any of them) is essentially constant.
431 questions
For questions about or related to the Krull dimension, which counts the length of the longest chain of prime ideals of a ring under inclusion.
430 questions
The Lie derivative gives a way to define the derivative of a tensor field in the direction of a vector field.
424 questions
Use the convention tag for questions about standard, cultural practices in mathematics.
424 questions
Ordered fields are 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 proofs related to un-orderability of certain fields.
422 questions
Discriminant of a polynomial $\;P\left(x\right) = a_{0} + a_{1}x + a_{2}x^{2} + \dots + a_{n}x^{n} \neq 0\,$
is defined as
\begin{align}
\Delta &= a_{n}^{2n-2}\prod_{ i < j } \big( r_i - r_j \big)^{2} = \left(-1\right)^{n\left(n-1\right)/2} a_{n}^{2n-2}\prod_{ i \neq j } \big( r_i - r_j \big)
\end{align}
where $\,r_1,\dots,r_n\,$ are roots of $P\left(x\right)$ (counting multiplicity)
421 questions
The Kronecker product of two matrices $\mathbf{A}_{(K\times L)}=\{a_{kl}\}$ and $\mathbf{B}_{(M\times N)}=\{b_{mn}\}$ which is denoted by $\mathbf{A}\otimes\mathbf{B}$ is defined as $$\mathbf{A}\otimes\mathbf{B}=\mathbf{C}_{(KM\times LN)}=\begin{bmatrix}a_{11}\mathbf{B} &\dots & a_{1L}\mathbf{B}\\\vdots &\ddots&\vdots\\a_{K1}\mathbf{B} &\dots & a_{KL}\mathbf{B}\end{bmatrix}$$
420 questions
For questions about the motivation behind mathematical concepts and results. These are often "why" questions.
419 questions
For questions on finding or applying slope, a number that describes both the direction and the steepness of a line.
415 questions
Intuitionistic logic refer constructive logic, a logical system avoiding deduction rules like *Reductio ad absurdum*.
415 questions
For questions about Morse theory, which is a branch of differential topology to analyze topology of manifolds by studying differentiable functions on them.
414 questions
For questions relevant to the general or subject-specific Graduate Record Examination, abbreviated GRE.
411 questions
Cyclotomic fields are fields where a primitive root of unity is added to the rational numbers. These fields are common in algebraic number theory.
410 questions
Questions on the Möbius function μ(n), an arithmetic function used in number theory.
408 questions
The difference of two prime consecutive prime numbers is the prime gap. $g_i := p_{i+1} - p_i$.
407 questions
Questions on Bernoulli numbers, a special sequence of rational numbers that arise as the coefficients in the power series expansions of certain elementary functions.
407 questions
In mathematics, the Grassmannian $\mathbf{Gr}(r, V)$ is a space which parameterizes all linear subspaces of a vector space $V$ of given dimension $r$.
406 questions
Questions on cylindrical coordinates, a coordinate system where points in space are represented by their distance to the $z$-axis ($r$), the angle the line joining the orthogonal projection of the point on the $xy$-plane and the origin makes with the positive $x$-axis ($\theta$) and the $z$ coordinate of the point.
406 questions
Let $X$ and $Y$ be normed spaces and $T: D(T)\rightarrow Y$ a linear operator, where $D(T)\subset X$. The operator $T$ is said to be unbounded if there exists a sequence $\{x_n\}\subset D(T)$ s.t. $$\| Tx_n\| \geq n\| x_n\| $$
404 questions
This tag is for questions regarding to "Solid of revolution", a three-dimensional object obtained by rotating a function in the plane about a line in the plane.
401 questions
In abstract algebra, a Dedekind domain or Dedekind ring, named after Richard Dedekind, is an integral domain in which every nonzero proper ideal factors into a product of prime ideals.
401 questions
For questions about directed graphs. In a directed graph, each edge is an ordered pair of vertices; we think of it as pointing from one to the other. Use with the (graph-theory) tag.
400 questions
This tag is for questions about regression analysis. In statistical modeling, regression analysis is a statistical process for estimating the relationships among variables. It includes many techniques for modeling and analyzing several variables, when the focus is on the relationship between a dependent variable and one or more independent variables (or 'predictors').
398 questions
This tag is used for questions on polynomials rings in an arbitrary number of variables related to different topics studied in ring theory and commutative algebra. Questions related to high-school polynomials level or similar should use the tag "polynomials".
396 questions
For questions on Classical Electromagnetism from a mathematical standpoint. This tag should not be the sole tag on a question.
396 questions
This tag is for questions relating to "Invariant Subspaces". Mathematically, an invariant subspace of a linear mapping $~T : V → V~$ from some vector space $~ V~$ to itself is a subspace $~W~$ of $~V~$ that is preserved by $~T~$.
395 questions
The tangent $TX$ of a smooth (real or complex) manifold is defined as disjoint union of all the tangent space at the points of $X$. This the first and natural example of vector bundle.
393 questions
Additive combinatorics is about giving combinatorial estimates of addition and subtraction operations on Abelian groups or other algebraic objects. Key words: sum set estimates, inverse theorems, graph theory techniques, crossing numbers, algebraic methods, Szemerédi’s theorem.
393 questions