Every idea

Ideas 9451–9600 of 10181.

Name	Kind	Subject
McKay conjecture	Theorem	Group theory and generalizations
Tight and overtwisted contact structures	Concept	Manifolds and cell complexes
Null-homotopic map	Definition	Algebraic topology
Finitely generated algebra	Concept	General algebraic systems
Kolmogorov extension theorem	Theorem	Probability theory and stochastic processes
Maximal order	Definition	Associative rings and algebras
Quasivariety	Concept	General algebraic systems
Bridge number	Definition	Manifolds and cell complexes
Linear and stable summation methods	Definition	Sequences, series, summability
Mean-field game	Concept	Game theory, economics, finance, and other social and behavioral sciences
Menger sponge	Example	General topology
Henselian ring	Definition	Commutative algebra
Lebesgue's density theorem	Theorem	Measure and integration
Classifying space	Concept	Algebraic topology
Euler transform	Concept	Sequences, series, summability
G-structure	Definition	Differential geometry
Inverse scattering transform	Definition	Dynamical systems and ergodic theory
Diffeomorphism group	Example	Global analysis, analysis on manifolds
Cobordism	Definition	Manifolds and cell complexes
Forgetful functor	Concept	Category theory; homological algebra
Pseudovariety	Definition	General algebraic systems
Commutative diagram	Concept	Category theory; homological algebra
Riemann–Lebesgue lemma	Theorem	Harmonic analysis on Euclidean spaces
Bézout domain	Definition	Commutative algebra
Riesz–Fischer theorem	Theorem	Functional analysis
Schottky group	Definition	Functions of a complex variable
GAGA	Theorem	Several complex variables and analytic spaces
Medial magma	Definition	Group theory and generalizations
Fubini's theorem for series	Theorem	Sequences, series, summability
Kullback–Leibler divergence	Definition	Information and communication theory, circuits
Simplicial set	Concept	Category theory; homological algebra
Hilbert class field	Concept	Number theory
Closed immersion	Concept	Algebraic geometry
Section of a vector bundle	Concept	Algebraic topology
Wang sequence	Theorem	Algebraic topology
Invariant set	Concept	Ordinary differential equations
Koebe quarter theorem	Theorem	Functions of a complex variable
Borromean rings	Example	Manifolds and cell complexes
Tensor field	Concept	Differential geometry
Algebraic number field	Definition	Number theory
Euler's thirty-six officers problem	Problem	Combinatorics
Pseudocomplement	Definition	Order, lattices, ordered algebraic structures
Yoneda Ext and extensions	Theorem	Category theory; homological algebra
Tangent bundle	Concept	Global analysis, analysis on manifolds
Proximity space	Concept	General topology
Brill–Noether theory	Definition	Algebraic geometry
Group representation	Concept	Group theory and generalizations
Vitali set	Counterexample	Measure and integration
Majorization	Definition	Real functions
Lorenz system	Example	Ordinary differential equations
Minkowski–Bouligand dimension	Concept	Measure and integration
Kernel	Definition	Category theory; homological algebra
Locally finite variety	Definition	General algebraic systems
Girth	Definition	Combinatorics
Fiber of a morphism	Definition	Algebraic geometry
Cauchy filter	Concept	General topology
Maximal chain	Definition	Order, lattices, ordered algebraic structures
Lie symmetry method	Definition	Ordinary differential equations
Cut locus	Definition	Differential geometry
Continuous group homomorphism	Definition	Topological groups, Lie groups
Resolvent set	Concept	Operator theory
Borel conjecture	Conjecture	Manifolds and cell complexes
Matrix multiplication exponent	Problem	Computer science
Maurer–Cartan form	Definition	Topological groups, Lie groups
Convergence along an ultrafilter	Definition	General topology
Error-correcting code	Definition	Information and communication theory, circuits
Knot Floer homology	Definition	Manifolds and cell complexes
Symplectic group	Object	Group theory and generalizations
Computability theory	Concept	Mathematical logic and foundations
Dispersive partial differential equation	Definition	Partial differential equations
Large cardinal	Concept	Mathematical logic and foundations
Schreier coset graph	Definition	Group theory and generalizations
Analytic capacity	Definition	Functions of a complex variable
Stable ∞-category	Concept	Category theory; homological algebra
Complex torus	Definition	Algebraic geometry
Separated morphism	Concept	Algebraic geometry
Formally real field	Concept	Field theory and polynomials
Ordered vector space	Definition	Functional analysis
Semilinear PDE	Definition	Partial differential equations
Lie symmetry method	Concept	Ordinary differential equations
Hearing the shape of a drum	Problem	Global analysis, analysis on manifolds
Exotic R4	Object	Manifolds and cell complexes
Center manifold	Concept	Ordinary differential equations
Quadratic variation	Concept	Probability theory and stochastic processes
Calabi–Weil rigidity	Corollary	Differential geometry
Schur's lemma	Lemma	Associative rings and algebras
Mittag-Leffler's theorem	Theorem	Functions of a complex variable
Compositum of fields	Definition	Field theory and polynomials
Rees matrix semigroup	Concept	Group theory and generalizations
Algorithmic randomness	Definition	Mathematical logic and foundations
Nörlund mean	Concept	Sequences, series, summability
Cut locus	Concept	Differential geometry
Abel–Dini theorem	Theorem	Sequences, series, summability
Differentiable curve	Definition	Differential geometry
Finite ring	Concept	Associative rings and algebras
Localization at a prime ideal	Concept	Commutative algebra
Rough path	Concept	Probability theory and stochastic processes
Upper half-plane	Object	Functions of a complex variable
Inner-outer factorization	Theorem	Functions of a complex variable
Spectral theorem for bounded normal operators	Theorem	Operator theory
Robbins conjecture	Theorem	Order, lattices, ordered algebraic structures
Rack and quandle	Concept	Manifolds and cell complexes
Integrable function	Concept	Measure and integration
Finite difference method	Concept	Numerical analysis
Artin's theorem on fixed fields	Theorem	Field theory and polynomials
Bondy's theorem	Theorem	Combinatorics
Lie algebra of a compact group is reductive	Theorem	Topological groups, Lie groups
Marsden–Weinstein reduction	Definition	Differential geometry
Summability method	Definition	Sequences, series, summability
Chern–Simons form	Concept	Differential geometry
Integral element	Definition	Commutative algebra
Baker–Campbell–Hausdorff formula	Theorem	Topological groups, Lie groups
Mayer–Vietoris sequence	Theorem	Algebraic topology
Eikonal equation	Definition	Partial differential equations
Separable algebra	Concept	Associative rings and algebras
Stinespring dilation theorem	Theorem	Functional analysis
Hilbert's tenth problem	Theorem	Number theory
Chebotarev's density theorem	Theorem	Number theory
Lattice	Definition	Order, lattices, ordered algebraic structures
Residually finite algebra	Concept	General algebraic systems
Permanent	Concept	Linear and multilinear algebra; matrix theory
Direct limit	Concept	Category theory; homological algebra
Hecke operator	Definition	Number theory
Sub-Gaussian distribution	Concept	Probability theory and stochastic processes
Laguerre–Pólya class	Concept	Functions of a complex variable
F. and M. Riesz theorem	Theorem	Functions of a complex variable
Gödel's incompleteness theorems	Theorem	Mathematical logic and foundations
Weyl's theorem on compact perturbations	Theorem	Operator theory
Jacobson radical	Concept	Commutative algebra
Matrix Lie group	Definition	Topological groups, Lie groups
Commutative magma	Concept	Group theory and generalizations
Hodge conjecture	Conjecture	Algebraic geometry
Inverse limit	Definition	Category theory; homological algebra
Khovanov homology	Concept	Manifolds and cell complexes
CAT(0) group	Concept	Group theory and generalizations
Schnirelmann density	Definition	Number theory
Lindelöf's theorem	Theorem	Functions of a complex variable
J-homomorphism	Definition	Algebraic topology
Associated graded ring	Definition	Commutative algebra
Local martingale	Concept	Probability theory and stochastic processes
Kovacic's algorithm	Concept	Ordinary differential equations
Nuclear space	Concept	Functional analysis
Prime ring	Definition	Associative rings and algebras
Primal algebra	Concept	General algebraic systems
A subgroup of order two in S3 is not normal	Example	Group theory and generalizations
Unary algebra	Concept	General algebraic systems
Fubini's theorem on differentiation	Theorem	Real functions
Metric outer measure	Definition	Measure and integration
Branch point	Definition	Functions of a complex variable
Square root of a positive operator	Definition	Operator theory