Every idea

Ideas 18751–18900 of 19934.

Name	Kind	Subject
Bombieri–De Giorgi–Giusti theorem	Theorem	Calculus of variations and optimal control; optimization
Balian–Low theorem	Theorem	Harmonic analysis on Euclidean spaces
Holographic principle	Concept	Relativity and gravitational theory
Schramm–Loewner evolution	Definition	Probability theory and stochastic processes
Conformal geometry	Definition	Differential geometry
Stability radius	Concept	Systems theory; control
Étale morphism	Definition	Algebraic geometry
Burnside problem	Problem	Group theory and generalizations
Three-term recurrence relation	Definition	Difference and functional equations
Dynamical billiards	Concept	Dynamical systems and ergodic theory
Cobb–Douglas production function	Concept	Game theory, economics, finance, and other social and behavioral sciences
Landau's necessary density conditions for sampling	Theorem	Information and communication theory, circuits
Smoothed analysis of the simplex method	Theorem	Operations research, mathematical programming
Numerical range	Concept	Operator theory
Poncelet's closure theorem	Theorem	Geometry
Zero dynamics	Definition	Systems theory; control
Enriched category	Definition	Category theory; homological algebra
Kontsevich formality theorem	Theorem	Differential geometry
Degree of exactness of a quadrature rule	Definition	Numerical analysis
Seismic anisotropy	Concept	Geophysics
Prandtl boundary layer equations	Concept	Fluid mechanics
Carathéodory's principle	Fact	Classical thermodynamics, heat transfer
Reed–Muller code	Concept	Information and communication theory, circuits
Factorization of polynomials over finite fields	Definition	Number theory
Delta derivative on a time scale	Concept	Real functions
Set cover problem	Problem	Operations research, mathematical programming
Non-amenability of free groups	Theorem	Abstract harmonic analysis
Tidal harmonic constituents	Definition	Geophysics
Spectrum of an operator	Definition	Operator theory
Tilting theory	Concept	Associative rings and algebras
Monad in functional programming	Definition	Computer science
Knot concordance	Definition	Manifolds and cell complexes
Volterra equation of the second kind	Definition	Integral equations
Quasistatic process	Definition	Classical thermodynamics, heat transfer
Automorphism	Definition	General algebraic systems
Cospherical points	Definition	Geometry
Symmetric kernel	Definition	Integral equations
Bôcher's theorem	Theorem	Potential theory
Elliptic operator	Concept	Operator theory
Einstein ring	Example	Relativity and gravitational theory
Classification of regular polytopes	Theorem	Geometry
Bondi mass	Concept	Relativity and gravitational theory
Day convolution	Definition	Category theory; homological algebra
Umbilical point	Concept	Differential geometry
Proof of the subgroup criterion	Proof	Group theory and generalizations
Almost periodic function	Definition	Abstract harmonic analysis
Cauchy's stress theorem	Theorem	Mechanics of deformable solids
Piezoelectricity	Concept	Mechanics of deformable solids
Sequence space	Concept	Functional analysis
List of small groups	Example	Group theory and generalizations
Conservation law	Definition	Partial differential equations
Recursively enumerable language	Definition	Mathematical logic and foundations
Skeleton of a category	Definition	Category theory; homological algebra
Generalized mean inequality	Theorem	Real functions
Radial basis function interpolation	Concept	Numerical analysis
Fermat point	Definition	Geometry
Morphism	Definition	Category theory; homological algebra
Toric ideal	Concept	Commutative algebra
Erdős–Stone theorem	Theorem	Combinatorics
Fenchel–Moreau theorem	Theorem	Convex and discrete geometry
Homotopy equivalence	Concept	Algebraic topology
Electrical resistivity tomography	Definition	Geophysics
Kummer theory	Concept	Number theory
DeGroot learning	Definition	Game theory, economics, finance, and other social and behavioral sciences
Denotational semantics	Definition	Computer science
Tight closure	Definition	Commutative algebra
Mathematical statistics	Concept	Statistics
Gibbs entropy	Definition	Statistical mechanics, structure of matter
Primitive recursive function	Definition	Mathematical logic and foundations
Stabilizability	Definition	Systems theory; control
Functional equations on groups	Definition	Difference and functional equations
Bode plot	Definition	Systems theory; control
Hardy space	Definition	Functions of a complex variable
Tidal harmonic constituents	Concept	Geophysics
Confluent hypergeometric function	Definition	Special functions
Finite-dimensional distributions	Concept	Probability theory and stochastic processes
Involution	Definition	General algebraic systems
Tannery's theorem	Theorem	Sequences, series, summability
Connected sum	Concept	Manifolds and cell complexes
Expenditure minimization problem	Problem	Game theory, economics, finance, and other social and behavioral sciences
Poisson–Mellin–Newton cycle	Concept	Integral transforms, operational calculus
Simple random sample	Concept	Statistics
Gaussian beam	Concept	Optics, electromagnetic theory
Toric ideal	Definition	Commutative algebra
Invertible operator	Definition	Operator theory
Percolation threshold	Definition	Probability theory and stochastic processes
Primitive permutation group	Concept	Group theory and generalizations
Rayleigh quotient iteration	Theorem	Numerical analysis
Robin boundary condition	Definition	Ordinary differential equations
Falling and rising factorials	Concept	Combinatorics
Madelung equations	Definition	Fluid mechanics
Ecological stability	Definition	Biology and other natural sciences
Carleson–Sjölin theorem	Theorem	Harmonic analysis on Euclidean spaces
Liouville property of graphs	Concept	Potential theory
Symmetric successive over-relaxation	Theorem	Numerical analysis
Monotone operator	Concept	Operator theory
Vlasov equation	Definition	Partial differential equations
Hahn polynomials	Concept	Special functions
Pseudoanalytic function	Concept	Functions of a complex variable
Priority method	Definition	Mathematical logic and foundations
Group ring	Definition	Associative rings and algebras
Full subcategory	Definition	Category theory; homological algebra
q-Pochhammer symbol	Concept	Combinatorics
Szegő kernel	Concept	Several complex variables and analytic spaces
Universal cover	Concept	Manifolds and cell complexes
Mal'cev term	Concept	General algebraic systems
Orders of the elements of S3	Example	Group theory and generalizations
Horndeski's theory	Definition	Relativity and gravitational theory
Algebraic K-theory of schemes	Concept	K-theory
Norton's theorem	Theorem	Information and communication theory, circuits
Laguerre's method	Theorem	Numerical analysis
Covering space	Definition	Manifolds and cell complexes
Map projection	Concept	Geophysics
Singer's theorem	Theorem	Dynamical systems and ergodic theory
Upper-convected time derivative	Definition	Fluid mechanics
MDS conjecture	Conjecture	Information and communication theory, circuits
Borg–Marchenko uniqueness theorem	Theorem	Ordinary differential equations
Newton series	Concept	Difference and functional equations
Projection method	Definition	Fluid mechanics
Monomorphism	Concept	Category theory; homological algebra
Circular restricted three-body problem	Problem	Mechanics of particles and systems
Homotopy principle	Concept	Global analysis, analysis on manifolds
Iwasawa theory	Concept	Number theory
Finitely presented algebra	Definition	Commutative algebra
Gain scheduling	Definition	Systems theory; control
Enriques surface	Concept	Algebraic geometry
Fredholm module	Concept	K-theory
Root system	Definition	Nonassociative rings and algebras
Curvature form	Definition	Differential geometry
Normal gravity and Somigliana's formula	Theorem	Geophysics
Information theory	Definition	Information and communication theory, circuits
Intermittency in turbulence	Concept	Fluid mechanics
Dolbeault cohomology	Concept	Several complex variables and analytic spaces
Zhang–Yeung inequality	Theorem	Information and communication theory, circuits
Deflection of the vertical	Concept	Geophysics
Cavity resonator	Concept	Optics, electromagnetic theory
Henstock–Kurzweil integral	Definition	Real functions
Gravitational microlensing	Concept	Astronomy and astrophysics
Kozai mechanism	Definition	Mechanics of particles and systems
Helgason Fourier transform	Definition	Abstract harmonic analysis
Rao–Blackwell theorem	Theorem	Statistics
Box spline	Definition	Approximations and expansions
Emissivity	Definition	Classical thermodynamics, heat transfer
Fisher–Tippett–Gnedenko theorem	Theorem	Probability theory and stochastic processes
Evolute	Concept	Differential geometry
Fox H-function	Definition	Special functions
Serre's finiteness theorem	Theorem	Algebraic topology
Kolmogorov–Sinai entropy	Definition	Dynamical systems and ergodic theory
Weissenberg number	Concept	Fluid mechanics
Rayleigh criterion	Definition	Optics, electromagnetic theory