Tags
A tag is a keyword or label that categorizes your question with other, similar questions.
The Orthogonal Procrustes Problem is a matrix approximation problem in linear algebra. In its classical form, one is given two matrices, $A$ and $B$, and is asked to find an orthogonal matrix $R$ that most closely maps $A$ to $B$.
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In complexity theory and computability theory, an oracle machine is an abstract machine used to study decision problems. It can be visualized as a Turing machine with a black box, called an oracle, which is able to solve certain decision problems in a single operation.
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Questions regarding the Newton series expansion of functions or other finite-difference based series expansions. Issues including convergence, calculation of coefficients, and bounds on remainders.
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Questions related to smooth actions of Lie groups (typically on symplectic or Poisson manifolds) which can be described by a Hamiltonian, called the moment map.
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A mesh is, by definition, a set of points and cells, when connected to form a network. This network can have many forms of geometry and topology, as will be discussed later. Often, meshes are also called grids, and that is generally related to the intrinsic organization of the mesh and/or when those meshes are related to Finite Differences problems.
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Local time is a stochastic process associated with semimartingale processes such as Brownian motion, that characterizes the amount of time a particle has spent at a given level.
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Integral geometry is the theory of measures on a geometrical space invariant under the symmetry group of that space.
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A holomorph of a group $G$ is a semidirect product $G \rtimes{\rm Aut}(G)$, where ${\rm Aut}(G)$ acts naturally over $G$. To be used with tags [group-theory] and [automorphism-group].
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A Fejér kernel is a summability kernel used to express the effect of Cesàro summation on Fourier series.
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Bergman spaces are basically the analytic functions that are absolutely integrable. They are denoted as $A^p(G) \subset L^p(G)$ where $G$ is a domain of $\mathbb{C}$
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For questions related to (term) rewriting systems (which are reduction systems in which rewrite rules apply to terms).
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This tag contains one of the two following problems:
a) to decide
when a number can be represented by a quadratic form.
b) to count
the number of representations of an arbitrary integer
by an arbitrary but fixed quadratic form.
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For questions on Polish notation. Polish notation, named for the Polish logician Jan Łukasiewicz, is a mathematical notation in which operators precede their operands.
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Model Predictive Control (MPC) is a process control method considering the system model and its predicted future optimization while respecting the defined constraints.
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A minor of a graph $\Gamma$ is a graph, obtained form a subgraph of $\Gamma$ by edge contractions. Robertson-Seymour theorem states that any family of graphs closed under finite minors can be defined by a finite set of forbidden minors (graphs that can not be minors of graphs from that family). A minor is called topological iff it is obtained form a subgraph by collapsing paths of degree-two vertices to single edges. To be used with [graph-theory] tag.
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About measures on infinite-dimensional topological vector spaces for which every continuous linear functional is Gaussian. Also in conjunction with abstract Wiener spaces and Gaussian processes.
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Use this tag for questions about short exact sequences of groups 1 → A → E → G → 1 such that A is in the center of E.
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The Birkhoff polytope is a convex polytope whose points are doubly stochastic matrices and whose vertices are permutation matrices.
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Vector autoregression is a stochastic process model used to capture the linear interdependencies among multiple time series.
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Abelian and Tauberian theorems are theorems giving conditions for two methods of summing divergent series to give the same result.
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For questions about or relating to Simulink, a graphical programming environment for modeling, simulating and analyzing multidomain dynamic systems.
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Sangaku are Japanese geometrical problems or theorems on wooden tablets which were placed as offerings at Shinto shrines or Buddhist temples during the Edo period.
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Lyapunov exponents (not to be confused with Lyapunov functions) are gadgets that describe the exponential rate at which the trajectories of infinitesimally close initial conditions diverge from one another under a certain time evolution. They were first considered in the context of the qualitative theory of ODE's; now they are used in a variety of disciplines; in particular they are fundamental objects in smooth ergodic theory.
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For questions about or related to the global dimension of a ring A, which is defined to be the supremum of the set of projective dimensions of all A-modules. To be used with (ring-theory), (homological-algebra) and (dimension-theory-algebra).
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For questions about difference sets of groups, their developments to symmetric designs, their existence and non-existence, multipliers, and other properties.
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Use this tag for questions about natural transformations from a functor defining a cohomology theory to itself. Common examples include Steenrod squares in mod 2 cohomology and Adams operations in K-theory.
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Verma modules, are objects in the representation theory of Lie algebras that can be used in the classification of irreducible representations of a complex semisimple Lie algebra
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Lie algebra cohomology is a cohomology theory for Lie algebras. It can be used to study the topology of Lie groups and homogeneous spaces by relating cohomological methods of Georges de Rham to properties of the Lie algebra.
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The notion for convergence of metric spaces that is a generalization of Hausdorff convergence.
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Differential Game Theory studies conflict in dynamical systems described by differential equations.
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This tag refers to questions about functions and measures of continuous variables, such as real and complex variables. This tag is in contrast with discrete variables, such as integers and enumerable sets.
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For questions related to conjugate gradient (method). It is an algorithm for the numerical solution of particular systems of linear equations, namely those whose matrix is positive-definite.
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