Every idea

Ideas 4201–4350 of 7806.

Name	Kind	Subject
Lie bracket of vector fields	Definition	Global analysis, analysis on manifolds
Kakeya set	Object	Measure and integration
Lefschetz number	Definition	Algebraic topology
Aleph number	Concept	Mathematical logic and foundations
HOMFLY polynomial	Definition	Manifolds and cell complexes
Dual matroid	Concept	Combinatorics
Veblen function	Definition	Mathematical logic and foundations
Variational inequality	Problem	Operator theory
Axiom of regularity	Definition	Mathematical logic and foundations
Ring spectrum	Definition	Algebraic topology
Fukaya category	Definition	Differential geometry
Linear topology	Concept	Commutative algebra
Immersion	Concept	Manifolds and cell complexes
Kummer theory	Definition	Number theory
Hopfian group	Definition	Group theory and generalizations
Einstein manifold	Definition	Differential geometry
Rigged Hilbert space	Concept	Functional analysis
Fundamental group of the circle	Theorem	Algebraic topology
Bertrand's test	Theorem	Sequences, series, summability
Projective dimension	Definition	Commutative algebra
Constructible universe	Object	Mathematical logic and foundations
Krylov–Bogolyubov averaging	Concept	Ordinary differential equations
Homology manifold	Concept	Manifolds and cell complexes
Young measure	Concept	Calculus of variations and optimal control; optimization
Cesàro summation	Definition	Sequences, series, summability
Pseudo-Riemannian manifold	Definition	Differential geometry
The left cosets of a subgroup of order two in S3	Example	Group theory and generalizations
Feit–Thompson theorem	Theorem	Group theory and generalizations
Caputo fractional derivative	Concept	Real functions
Ring of invariants	Concept	Commutative algebra
Kähler–Einstein metric	Definition	Several complex variables and analytic spaces
Exotic sphere	Object	Manifolds and cell complexes
Fundamental recurrence formulas	Theorem	Sequences, series, summability
Wynn's epsilon algorithm	Concept	Numerical analysis
Invariance of domain	Theorem	Algebraic topology
Abel–Poisson summation of Fourier series	Definition	Harmonic analysis on Euclidean spaces
Hadamard conjecture	Conjecture	Combinatorics
Normal closure	Concept	Field theory and polynomials
Schwarzschild metric	Example	Relativity and gravitational theory
Rees algebra	Definition	Commutative algebra
Barrelled space	Definition	Functional analysis
Homogeneous ideal	Concept	Commutative algebra
Tauberian condition	Concept	Sequences, series, summability
Besicovitch covering theorem	Theorem	Measure and integration
Hasse–Weil zeta function	Definition	Algebraic geometry
Schwarzian derivative	Concept	Functions of a complex variable
Balanced set	Definition	Functional analysis
Orientability	Concept	Manifolds and cell complexes
Seifert fiber space	Definition	Manifolds and cell complexes
Summation of families over arbitrary index sets	Concept	Sequences, series, summability
Hurewicz fibration	Definition	Algebraic topology
Convergence of filters	Concept	General topology
Building	Definition	Group theory and generalizations
Virtual knot	Concept	Manifolds and cell complexes
Dirichlet process	Definition	Probability theory and stochastic processes
Alexandrov space	Concept	Differential geometry
FK-space	Concept	Functional analysis
Sparse matrix	Definition	Numerical analysis
Massey product	Definition	Algebraic topology
Polytope combinatorics	Definition	Convex and discrete geometry
Kontsevich integral	Concept	Manifolds and cell complexes
Global dimension	Definition	Commutative algebra
Absolute neighborhood retract	Definition	General topology
Splitting of prime ideals	Definition	Number theory
Explicit formula	Theorem	Number theory
Hawaiian earring	Example	Algebraic topology
Flat module	Concept	Commutative algebra
Pick matrix	Definition	Functions of a complex variable
Enneper surface	Example	Differential geometry
Field trace	Definition	Field theory and polynomials
Hardy–Littlewood maximal function	Definition	Harmonic analysis on Euclidean spaces
NIP theory	Concept	Mathematical logic and foundations
Lebesgue decomposition theorem	Theorem	Measure and integration
Strong Cesàro summability	Concept	Sequences, series, summability
Turing machine	Concept	Mathematical logic and foundations
Summation in topological groups	Definition	Sequences, series, summability
Classical group	Concept	Group theory and generalizations
Padé approximant	Definition	Approximations and expansions
Egorov's theorem	Theorem	Measure and integration
Finitely presented algebra	Concept	Commutative algebra
Tychonoff space	Definition	General topology
Positive operator	Concept	Operator theory
Real closure	Concept	Field theory and polynomials
Model theory of algebraically closed fields	Definition	Field theory and polynomials
Universally measurable set	Definition	Measure and integration
Point process	Definition	Probability theory and stochastic processes
Orders of the elements of the integers modulo 6	Example	Group theory and generalizations
Product measure	Concept	Measure and integration
Complete local ring	Definition	Commutative algebra
Fundamental theorem of Riemannian geometry	Theorem	Differential geometry
Jordan's theorem on primitive groups containing a prime cycle	Theorem	Group theory and generalizations
Artin reciprocity law	Theorem	Number theory
Riemann curvature tensor	Definition	Differential geometry
Summability field of a matrix method	Concept	Sequences, series, summability
Space of functions vanishing at infinity	Definition	Functional analysis
Witt group	Definition	Number theory
Brouwer–Heyting–Kolmogorov interpretation	Concept	Mathematical logic and foundations
Euler transform	Definition	Sequences, series, summability
Darboux function	Concept	Real functions
Steiner system	Concept	Combinatorics
Fixed-point iteration	Definition	Operator theory
Riemannian manifold	Concept	Differential geometry
Theta function	Definition	Number theory
Arithmetical hierarchy	Concept	Mathematical logic and foundations
Frobenius method	Definition	Ordinary differential equations
Runge–Kutta methods	Concept	Numerical analysis
Kunen's inconsistency theorem	Theorem	Mathematical logic and foundations
Wreath product	Definition	Group theory and generalizations
Purely transcendental extension	Definition	Field theory and polynomials
Freudenthal suspension theorem	Theorem	Algebraic topology
Haken manifold	Concept	Manifolds and cell complexes
Manifold with boundary	Concept	Manifolds and cell complexes
Quadratic field	Definition	Number theory
Neutral differential equation	Definition	Ordinary differential equations
Jacobson ring	Concept	Commutative algebra
Mittag-Leffler star	Definition	Functions of a complex variable
Ornstein–Uhlenbeck process	Definition	Probability theory and stochastic processes
Markov theorem	Theorem	Manifolds and cell complexes
The integers modulo 2 and the group of signs are isomorphic	Example	Group theory and generalizations
Quantifier elimination	Concept	Mathematical logic and foundations
Point spectrum	Concept	Operator theory
Purely inseparable extension	Definition	Field theory and polynomials
Schwarz–Christoffel mapping	Concept	Functions of a complex variable
Fort space	Counterexample	General topology
Radical extension	Definition	Field theory and polynomials
k-vertex-connected graph	Concept	Combinatorics
The exponential map from the additive reals to the positive reals	Example	Group theory and generalizations
Serre's problem on projective modules	Problem	Commutative algebra
Sphere theorem	Theorem	Differential geometry
Schaefer's fixed point theorem	Theorem	Operator theory
Characteristic class	Concept	Algebraic topology
Kähler differentials	Concept	Commutative algebra
Jacobson radical	Definition	Commutative algebra
Mertens' theorems	Theorem	Number theory
Curvature of a curve	Concept	Differential geometry
Local homeomorphism	Definition	General topology
Thue–Morse sequence	Object	Number theory
Wu's formula	Theorem	Manifolds and cell complexes
Lp space	Definition	Functional analysis
von Neumann's inequality	Theorem	Operator theory
Crystallographic group	Concept	Group theory and generalizations
Omitting types theorem	Theorem	Mathematical logic and foundations
Morse homology	Definition	Manifolds and cell complexes
Ideal norm	Definition	Number theory
Rectifiable set	Concept	Measure and integration
Quillen–Suslin theorem	Theorem	Commutative algebra
Dedekind domain	Concept	Commutative algebra
Sturm–Liouville theory	Definition	Ordinary differential equations
L-infinity space	Definition	Functional analysis
Irreducible ideal	Concept	Commutative algebra