Every idea

Ideas 13801–13950 of 14167.

Name	Kind	Subject
Line segment	Definition	Convex and discrete geometry
Uniserial module	Concept	Associative rings and algebras
Thin plate spline	Definition	Approximations and expansions
Order filter	Concept	Order, lattices, ordered algebraic structures
Duality in category theory	Definition	Category theory; homological algebra
Racah polynomials	Definition	Special functions
Cotangent space of a local ring	Concept	Commutative algebra
Difference algebra	Concept	Field theory and polynomials
Abel summation	Definition	Sequences, series, summability
Subharmonic function	Concept	Potential theory
Frobenius group	Definition	Group theory and generalizations
Lieb–Liniger integral equation	Example	Statistical mechanics, structure of matter
Operator exponential and translation	Proposition	Integral transforms, operational calculus
CR function	Definition	Several complex variables and analytic spaces
Axiom A	Concept	Dynamical systems and ergodic theory
Maximal torus	Definition	Topological groups, Lie groups
Trace class operator	Concept	Operator theory
Horner's method	Definition	Computer science
Parabolic subgroup	Concept	Topological groups, Lie groups
Lumer–Phillips theorem	Theorem	Operator theory
Morrey's inequality	Theorem	Functional analysis
Trace operator	Concept	Functional analysis
Hadamard product	Definition	Linear and multilinear algebra; matrix theory
Osculating circle	Definition	Differential geometry
Positive cone	Concept	Functional analysis
Littlewood's Tauberian theorem	Theorem	Sequences, series, summability
Lattice in a Lie group	Definition	Topological groups, Lie groups
Spectrum	Definition	Algebraic topology
Plane curve	Definition	Algebraic geometry
Inverse tangent integral	Definition	Special functions
Weierstrass equation	Concept	Algebraic geometry
Algebraic logic	Concept	Mathematical logic and foundations
Aperiodic set of prototiles	Concept	Convex and discrete geometry
Henselian field	Definition	Field theory and polynomials
Pushout	Definition	Category theory; homological algebra
Myers–Steenrod theorem	Theorem	Differential geometry
Cubic Hermite spline	Definition	Approximations and expansions
Exact category in the sense of Barr	Definition	Category theory; homological algebra
Hairy ball theorem	Theorem	Manifolds and cell complexes
Stein space	Concept	Several complex variables and analytic spaces
Lattice (group)	Definition	Number theory
Summation of families over arbitrary index sets	Definition	Sequences, series, summability
Condensed set	Definition	Category theory; homological algebra
Little q-Jacobi polynomials	Concept	Special functions
Character of a representation	Definition	Group theory and generalizations
O'Nan–Scott theorem	Theorem	Group theory and generalizations
Whittaker–Shannon interpolation formula	Theorem	Information and communication theory, circuits
Abstract Wiener space	Definition	Measure and integration
Primitive ideal	Definition	Associative rings and algebras
Doob martingale	Example	Probability theory and stochastic processes
Band matrix	Concept	Linear and multilinear algebra; matrix theory
Oracle machine	Concept	Mathematical logic and foundations
Anderson–Kadec theorem	Theorem	Manifolds and cell complexes
Relatively complemented lattice	Definition	Order, lattices, ordered algebraic structures
Duality in category theory	Concept	Category theory; homological algebra
Projective morphism	Concept	Algebraic geometry
Chudnovsky algorithm	Definition	Number theory
Change detection	Problem	Statistics
3-manifold	Definition	Manifolds and cell complexes
Zonotope	Concept	Convex and discrete geometry
Proper cone	Concept	Convex and discrete geometry
Bernstein–Bézier form	Concept	Approximations and expansions
Asymptotic expansion from poles of a Mellin transform	Definition	Integral transforms, operational calculus
Complete elliptic integral of the first kind	Definition	Special functions
No-retraction theorem	Theorem	Algebraic topology
Fisher–Neyman factorization theorem	Theorem	Statistics
Current	Definition	Calculus of variations and optimal control; optimization
Four-vertex theorem	Theorem	Differential geometry
Normal Moore space problem	Problem	General topology
Locally compact abelian group	Definition	Topological groups, Lie groups
Inherently nonfinitely based algebra	Concept	General algebraic systems
Triebel–Lizorkin space	Definition	Functional analysis
Massey product	Concept	Algebraic topology
Girsanov theorem	Theorem	Probability theory and stochastic processes
Zolotarev polynomials	Definition	Approximations and expansions
Spectral theory of dynamical systems	Concept	Dynamical systems and ergodic theory
Real analytic manifold	Concept	Several complex variables and analytic spaces
Monomial ideal	Definition	Commutative algebra
Interior operator	Concept	Order, lattices, ordered algebraic structures
Solvable by radicals	Definition	Field theory and polynomials
Golden–Thompson inequality	Theorem	Linear and multilinear algebra; matrix theory
Sard's theorem	Theorem	Global analysis, analysis on manifolds
Successor order	Definition	Order, lattices, ordered algebraic structures
Strongly pseudoconvex domain	Concept	Several complex variables and analytic spaces
Polar space	Concept	Geometry
Hunt process	Concept	Probability theory and stochastic processes
Undecidability of the halting problem	Theorem	Mathematical logic and foundations
Symmetric and self-reciprocal kernels	Definition	Integral transforms, operational calculus
Curve-shortening flow	Definition	Differential geometry
Almost periodic sequence	Concept	Difference and functional equations
Tensor decomposition	Definition	Linear and multilinear algebra; matrix theory
Word problem for free lattices	Theorem	Order, lattices, ordered algebraic structures
Stone–von Neumann theorem	Theorem	Topological groups, Lie groups
Essentially self-adjoint operator	Definition	Operator theory
Euler integral for the gamma function	Theorem	Special functions
Finite-rank operator	Concept	Operator theory
Synge's theorem	Theorem	Differential geometry
Monogenic function	Definition	Functions of a complex variable
Hopf manifold	Example	Several complex variables and analytic spaces
Fourier series of Bernoulli polynomials	Example	Harmonic analysis on Euclidean spaces
Martin's axiom	Definition	Mathematical logic and foundations
Christoffel symbols	Definition	Differential geometry
Congruence lattice	Definition	General algebraic systems
Reeb stability theorem	Theorem	Manifolds and cell complexes
Kervaire invariant problem	Problem	Algebraic topology
Parametrix	Concept	Global analysis, analysis on manifolds
Weil divisor	Concept	Algebraic geometry
Topological manifold	Definition	Manifolds and cell complexes
Flag variety	Definition	Algebraic geometry
Prime ring	Concept	Associative rings and algebras
Symbol class	Definition	Partial differential equations
Hurewicz theorem	Theorem	Algebraic topology
Transform pair	Concept	Integral transforms, operational calculus
Dehn surgery	Concept	Manifolds and cell complexes
CSP dichotomy theorem	Theorem	General algebraic systems
Singular perturbation	Definition	Ordinary differential equations
Boutet de Monvel's embedding theorem	Theorem	Several complex variables and analytic spaces
Curvature form	Concept	Differential geometry
Well-founded order	Definition	Order, lattices, ordered algebraic structures
Allen–Cahn equation	Definition	Partial differential equations
Moment map	Concept	Differential geometry
Heat potential	Concept	Partial differential equations
Linear discriminant analysis	Concept	Statistics
Subadditive function	Definition	Difference and functional equations
Steiner conic	Definition	Geometry
First and second variation of arc length	Theorem	Differential geometry
Gowers norm	Concept	Number theory
Theta correspondence	Concept	Number theory
Fundamental groupoid	Concept	Algebraic topology
Category of posets	Concept	Category theory; homological algebra
Cauchy's functional equation	Problem	Difference and functional equations
Power series in several variables	Definition	Several complex variables and analytic spaces
Cartan matrix of an algebra	Concept	Associative rings and algebras
Kohn Laplacian	Concept	Several complex variables and analytic spaces
Bernstein's theorem on monotone functions	Theorem	Real functions
Radial basis function	Concept	Approximations and expansions
Fuchsian equation	Concept	Ordinary differential equations
Hirsch conjecture	Counterexample	Convex and discrete geometry
Littlewood–Paley square function	Definition	Harmonic analysis on Euclidean spaces
Quadratic variation	Definition	Probability theory and stochastic processes
Normal form	Definition	Ordinary differential equations
Universal bundle	Definition	Algebraic topology
Beth number	Definition	Mathematical logic and foundations
CR manifold	Concept	Several complex variables and analytic spaces
Lawson topology	Concept	Order, lattices, ordered algebraic structures
Functional equation of the gamma function	Theorem	Special functions
Moishezon manifold	Definition	Several complex variables and analytic spaces
Hermite equation	Example	Ordinary differential equations
Alexandrov's theorem on polyhedra	Theorem	Convex and discrete geometry
Regular cardinal	Definition	Mathematical logic and foundations