Every idea

Ideas 18001–18150 of 19838.

Name	Kind	Subject
Alexander polynomial	Definition	Manifolds and cell complexes
Chattering control	Definition	Calculus of variations and optimal control; optimization
Fredholm minors	Definition	Integral equations
Kappa mechanism	Concept	Astronomy and astrophysics
Haag–Łopuszański–Sohnius theorem	Theorem	Quantum theory
Lie subalgebra	Concept	Nonassociative rings and algebras
Small oscillations about equilibrium	Definition	Mechanics of particles and systems
Lie algebra of a Lie group	Concept	Topological groups, Lie groups
Unirational variety	Definition	Algebraic geometry
Pseudocompact space	Definition	General topology
Gamma of one half	Proposition	Special functions
Nonstandard analysis	Concept	Real functions
Equipartition theorem	Theorem	Statistical mechanics, structure of matter
Sequential space	Concept	General topology
Baker's theorem	Theorem	Number theory
Corona theorem	Theorem	Functions of a complex variable
Luzin N property	Concept	Real functions
Regular category	Definition	Category theory; homological algebra
Weak and strong extremum	Concept	Calculus of variations and optimal control; optimization
Pseudocomplement	Concept	Order, lattices, ordered algebraic structures
Richardson extrapolation	Concept	Numerical analysis
Riemann–Roch theorem	Theorem	Algebraic geometry
Wirtinger derivatives	Concept	Functions of a complex variable
Cosmic distance ladder	Definition	Astronomy and astrophysics
Bott periodicity theorem	Theorem	Algebraic topology
Morley rank	Concept	Mathematical logic and foundations
Thermodynamic work	Definition	Classical thermodynamics, heat transfer
Symmetry in quantum mechanics	Concept	Quantum theory
Series in Banach spaces	Concept	Sequences, series, summability
Divisor class group	Concept	Commutative algebra
Lattice (group)	Concept	Number theory
Stopping time	Concept	Probability theory and stochastic processes
Antithetic variates	Theorem	Numerical analysis
John ellipsoid	Concept	Convex and discrete geometry
Feder–Vardi dichotomy conjecture	Conjecture	Computer science
Szegő limit theorems	Theorem	Operator theory
Huffman coding	Definition	Information and communication theory, circuits
Galois theory	Concept	Field theory and polynomials
Hilbert's thirteenth problem	Problem	Real functions
Contact manifold	Definition	Differential geometry
Incomplete beta function	Concept	Special functions
Chemical potential	Definition	Classical thermodynamics, heat transfer
Category of sets	Example	Category theory; homological algebra
Whitehead product	Definition	Algebraic topology
Free lattice	Concept	Order, lattices, ordered algebraic structures
Robertson–Seymour theorem	Theorem	Combinatorics
Sufficient statistic	Concept	Statistics
Penrose–Hawking singularity theorems	Theorem	Relativity and gravitational theory
Essential supremum	Concept	Measure and integration
Field trace	Concept	Field theory and polynomials
Laplace transform of the Heaviside step function	Example	Integral transforms, operational calculus
Mark and recapture estimation	Definition	Statistics
Method of moments in electromagnetics	Definition	Optics, electromagnetic theory
Maximum length sequence	Definition	Information and communication theory, circuits
Hilbert's fifteenth problem	Problem	Algebraic geometry
Stieltjes function	Concept	Real functions
Stochastic difference equation	Concept	Difference and functional equations
Thermal efficiency	Definition	Classical thermodynamics, heat transfer
Gödel's completeness theorem	Theorem	Mathematical logic and foundations
Angular spectrum method	Definition	Optics, electromagnetic theory
Ideal class group	Concept	Number theory
Chain complex	Concept	Category theory; homological algebra
Jackknife	Concept	Statistics
Easton's theorem	Theorem	Mathematical logic and foundations
Arnold tongue	Concept	Dynamical systems and ergodic theory
Metacompact space	Concept	General topology
Arthur–Merlin protocol	Definition	Computer science
Wilks' theorem	Theorem	Statistics
Funk transform	Concept	Integral transforms, operational calculus
Munk's wind-driven circulation model	Definition	Geophysics
McKay conjecture	Theorem	Group theory and generalizations
Tight and overtwisted contact structures	Concept	Manifolds and cell complexes
Parker spiral	Definition	Astronomy and astrophysics
Jackson's inequality	Theorem	Approximations and expansions
Instant centre of rotation	Concept	Mechanics of particles and systems
Null-homotopic map	Definition	Algebraic topology
Prandtl–Glauert transformation	Proposition	Fluid mechanics
Bogoliubov transformation	Concept	Quantum theory
Gibbs–Bogoliubov inequality	Theorem	Statistical mechanics, structure of matter
Screw theory	Definition	Mechanics of particles and systems
Finitely generated algebra	Concept	General algebraic systems
Kolmogorov extension theorem	Theorem	Probability theory and stochastic processes
Abstract polytope	Concept	Convex and discrete geometry
Uniqueness of solutions given initial values	Proposition	Difference and functional equations
Elementary subgroup	Definition	K-theory
Triangle center	Concept	Geometry
Griffith criterion	Proposition	Mechanics of deformable solids
Maximal order	Definition	Associative rings and algebras
Quasivariety	Concept	General algebraic systems
Discrete harmonic function	Concept	Potential theory
Bridge number	Definition	Manifolds and cell complexes
Gale diagram	Definition	Convex and discrete geometry
Electromagnetic tensor	Concept	Optics, electromagnetic theory
Normal modes of the Earth	Definition	Geophysics
Solution of recurrences by generating functions	Concept	Difference and functional equations
Rodrigues' rotation formula	Proposition	Mechanics of particles and systems
Fracture mechanics	Definition	Mechanics of deformable solids
Linear and stable summation methods	Definition	Sequences, series, summability
Propagation of uncertainty	Concept	Numerical analysis
Mean-field game	Concept	Game theory, economics, finance, and other social and behavioral sciences
Matrix population model	Concept	Biology and other natural sciences
Costate equation	Concept	Calculus of variations and optimal control; optimization
Dimension group	Concept	K-theory
Eddington luminosity	Concept	Astronomy and astrophysics
Pfister form	Definition	Number theory
Information content	Definition	Information and communication theory, circuits
Menger sponge	Example	General topology
Henselian ring	Definition	Commutative algebra
Lebesgue's density theorem	Theorem	Measure and integration
Uniqueness of Haar measure	Theorem	Measure and integration
Bounded symmetric domain	Definition	Several complex variables and analytic spaces
Classifying space	Concept	Algebraic topology
Euler transform	Concept	Sequences, series, summability
Riemann–Lebesgue lemma for abelian groups	Theorem	Abstract harmonic analysis
Stability of matter	Theorem	Quantum theory
G-structure	Definition	Differential geometry
Inverse scattering transform	Definition	Dynamical systems and ergodic theory
Wigner distribution function	Definition	Quantum theory
Diffeomorphism group	Example	Global analysis, analysis on manifolds
Borsuk's conjecture	Counterexample	Convex and discrete geometry
Bulk modulus	Definition	Mechanics of deformable solids
Focal mechanism	Definition	Geophysics
Cobordism	Definition	Manifolds and cell complexes
Van Cittert–Zernike theorem	Theorem	Optics, electromagnetic theory
Estimating equations	Concept	Statistics
Gosper's algorithm	Definition	Special functions
MLC conjecture	Conjecture	Dynamical systems and ergodic theory
Regularization of ill-posed problems	Concept	Numerical analysis
Rogers–Ramanujan continued fraction	Definition	Number theory
Fujiki class C	Definition	Several complex variables and analytic spaces
Bayesian search theory	Concept	Operations research, mathematical programming
True quantified Boolean formula	Problem	Computer science
Forgetful functor	Concept	Category theory; homological algebra
Pseudovariety	Definition	General algebraic systems
Cartan's test for involutivity	Theorem	Global analysis, analysis on manifolds
Commutative diagram	Concept	Category theory; homological algebra
Lelong number	Concept	Several complex variables and analytic spaces
Cox–de Boor recursion	Theorem	Approximations and expansions
Inertia tensor and principal axes	Concept	Mechanics of particles and systems
Chemical potential	Concept	Classical thermodynamics, heat transfer
Morlet wavelet	Example	Harmonic analysis on Euclidean spaces
Riemann–Lebesgue lemma	Theorem	Harmonic analysis on Euclidean spaces
Bézout domain	Definition	Commutative algebra
Cosmological constant	Concept	Relativity and gravitational theory
BCMP network	Theorem	Probability theory and stochastic processes
Small oscillations about equilibrium	Concept	Mechanics of particles and systems
Chronology protection conjecture	Conjecture	Relativity and gravitational theory
Riesz–Fischer theorem	Theorem	Functional analysis
Vorticity equation	Definition	Fluid mechanics
Hohenberg–Kohn theorems	Theorem	Quantum theory