Every idea

Ideas 13501–13650 of 14167.

Name	Kind	Subject
Intersection body	Concept	Convex and discrete geometry
Eigenvalue perturbation	Definition	Linear and multilinear algebra; matrix theory
Associative quotient of a magma	Definition	Group theory and generalizations
Schur–Horn theorem	Theorem	Linear and multilinear algebra; matrix theory
Galerkin method	Concept	Numerical analysis
Mal'cev term	Definition	General algebraic systems
Function of exponential order	Definition	Integral transforms, operational calculus
Score test	Concept	Statistics
Semi-continuity	Definition	Real functions
Generic flatness	Theorem	Algebraic geometry
Completion of a topological group	Definition	Topological groups, Lie groups
Perimeter of a set	Concept	Calculus of variations and optimal control; optimization
Structure	Definition	Mathematical logic and foundations
Divisor class group	Definition	Commutative algebra
Sine and cosine series	Concept	Harmonic analysis on Euclidean spaces
Injectivity radius	Concept	Differential geometry
Glimm scheme	Concept	Partial differential equations
Pseudoconvexity	Definition	Several complex variables and analytic spaces
Numerical range	Definition	Operator theory
Castelnuovo–Mumford regularity	Concept	Commutative algebra
Hurewicz fibration	Concept	Algebraic topology
Universal coalgebra	Definition	General algebraic systems
Circle average	Concept	Potential theory
Homogeneity equation	Concept	Difference and functional equations
de Branges space	Definition	Functional analysis
Lagrange polynomial	Concept	Approximations and expansions
Complex torus	Concept	Algebraic geometry
Flat norm	Concept	Calculus of variations and optimal control; optimization
Bounded symmetric domain	Concept	Several complex variables and analytic spaces
Canonical height	Definition	Dynamical systems and ergodic theory
Cheeger constant	Concept	Combinatorics
Brody hyperbolicity	Concept	Several complex variables and analytic spaces
Hypergeometric differential equation	Definition	Special functions
Exponential map	Concept	Differential geometry
Non-uniform rational B-spline	Concept	Numerical analysis
Brauer–Manin obstruction	Definition	Algebraic geometry
Prime knot	Definition	Manifolds and cell complexes
Infinite compositions of functions	Definition	Sequences, series, summability
Second-order arithmetic	Definition	Mathematical logic and foundations
Hodge structure	Definition	Algebraic geometry
Hazard function	Concept	Statistics
Continuous and residual spectrum	Definition	Operator theory
Measure with density	Concept	Measure and integration
Germ	Definition	General topology
Stochastic differential equation	Definition	Probability theory and stochastic processes
Abelian category	Concept	Category theory; homological algebra
Girard's theorem	Theorem	Geometry
Stieltjes moment problem	Problem	Integral transforms, operational calculus
Affine variety	Definition	Algebraic geometry
Permutation test	Definition	Statistics
Rigid analytic space	Concept	Algebraic geometry
Minkowski–Hlawka theorem	Theorem	Number theory
Branched covering	Concept	Manifolds and cell complexes
Dirichlet eigenvalue	Definition	Partial differential equations
Lattice of subvarieties	Definition	General algebraic systems
Euler's continued fraction formula	Theorem	Sequences, series, summability
Fractional ideal	Concept	Commutative algebra
Ree groups	Object	Group theory and generalizations
Hellinger distance	Definition	Statistics
Sz.-Nagy's dilation theorem	Theorem	Operator theory
Incomplete gamma function	Concept	Special functions
Grushko theorem	Theorem	Group theory and generalizations
Fisher's exact test	Definition	Statistics
Voter model	Example	Probability theory and stochastic processes
Thurston norm	Definition	Manifolds and cell complexes
Böttcher's equation	Theorem	Dynamical systems and ergodic theory
Kadomtsev–Petviashvili equation	Definition	Partial differential equations
Sharkovskii's theorem	Theorem	Dynamical systems and ergodic theory
Schottky group	Concept	Functions of a complex variable
Order filter	Definition	Order, lattices, ordered algebraic structures
Zariski's lemma	Lemma	Commutative algebra
Balinski's theorem	Theorem	Convex and discrete geometry
q-gamma function	Definition	Special functions
Sierpiński's theorem on measurable midpoint convex functions	Theorem	Real functions
Approximation by convolution with mollifiers	Theorem	Functional analysis
Buchberger's algorithm	Definition	Commutative algebra
Evolute	Definition	Differential geometry
Hessenberg matrix	Concept	Linear and multilinear algebra; matrix theory
Boundary layer	Concept	Ordinary differential equations
Integral transform	Concept	Integral transforms, operational calculus
Hilbert's twenty-third problem	Problem	Calculus of variations and optimal control; optimization
Homology with coefficients	Definition	Algebraic topology
Abscissa of absolute convergence	Concept	Integral transforms, operational calculus
Autocorrelation function	Concept	Statistics
Homotopy groups of spheres	Concept	Algebraic topology
Dini derivative	Definition	Real functions
Adjoint state method	Concept	Calculus of variations and optimal control; optimization
Barnes G-function	Definition	Special functions
Artin–Schreier theorem on formally real fields	Theorem	Field theory and polynomials
Amitsur–Levitzki theorem	Theorem	Associative rings and algebras
Brjuno number	Definition	Dynamical systems and ergodic theory
Successive minima	Concept	Number theory
Error of best approximation	Concept	Approximations and expansions
Frequentist inference	Concept	Statistics
Going-down theorem	Theorem	Commutative algebra
Mazur–Orlicz theorem	Theorem	Sequences, series, summability
Arnold's classification of simple singularities	Theorem	Several complex variables and analytic spaces
Stationary set	Concept	Mathematical logic and foundations
Chebyshev constant	Definition	Potential theory
Hill differential equation	Example	Ordinary differential equations
Bieberbach theorems	Theorem	Group theory and generalizations
Sturm separation theorem	Theorem	Ordinary differential equations
Random dynamical system	Definition	Dynamical systems and ergodic theory
Nagata's example of a Noetherian ring of infinite dimension	Counterexample	Commutative algebra
von Neumann bounded set	Definition	Functional analysis
Schläfli symbol	Definition	Geometry
HNN extension	Concept	Group theory and generalizations
Quasi-analytic function	Concept	Real functions
Unirational variety	Concept	Algebraic geometry
Robin constant	Definition	Potential theory
Limit set	Concept	Dynamical systems and ergodic theory
Excellent ring	Concept	Commutative algebra
Zero morphism	Concept	Category theory; homological algebra
Generalized cohomology theory	Definition	Algebraic topology
Isomorphism theorem for measure algebras	Theorem	Measure and integration
Hilbert's Theorem 90	Theorem	Field theory and polynomials
Order of a PDE	Definition	Partial differential equations
Holomorphic functional calculus	Concept	Operator theory
Malcev completion	Definition	Topological groups, Lie groups
Birkhoff–Frink representation of algebraic closure systems	Theorem	General algebraic systems
(∞,1)-category	Concept	Category theory; homological algebra
Uniform boundedness principle	Theorem	Functional analysis
Finite field arithmetic	Concept	Field theory and polynomials
Dirichlet energy	Concept	Potential theory
Dissipative operator	Definition	Operator theory
Choquet capacity	Definition	Measure and integration
Operator theory	Concept	Operator theory
Projective object	Definition	Category theory; homological algebra
Chebyshev–Markov–Stieltjes inequalities	Theorem	Integral transforms, operational calculus
Reciprocal gamma function	Definition	Special functions
Heat kernel	Definition	Partial differential equations
Period map	Concept	Several complex variables and analytic spaces
Bonferroni correction	Definition	Statistics
Quantum invariant of 3-manifolds	Concept	Manifolds and cell complexes
Reflexive operator algebra	Definition	Operator theory
Gromov's compactness theorem	Theorem	Differential geometry
A Dedekind UFD is a PID	Proposition	Commutative algebra
Finitely based algebra	Concept	General algebraic systems
Triangulation	Concept	Manifolds and cell complexes
Scaling function and refinement equation	Concept	Harmonic analysis on Euclidean spaces
Synthetic geometry	Definition	Geometry
Semilocal ring	Definition	Associative rings and algebras
One-parameter subgroup	Concept	Topological groups, Lie groups
Hilbert's axioms	Definition	Geometry
Langlands classification	Theorem	Topological groups, Lie groups
Automorphism group of a bounded domain is a Lie group	Theorem	Several complex variables and analytic spaces
Poincaré–Lindstedt method	Concept	Ordinary differential equations
Eilenberg–Steenrod axioms	Concept	Algebraic topology
Perspective projection	Concept	Geometry
Doob decomposition theorem	Theorem	Probability theory and stochastic processes