Every idea

Ideas 3901–4050 of 14183.

Name	Kind	Subject
Bachmann's reflection geometry	Definition	Geometry
Hilbert matrix	Example	Linear and multilinear algebra; matrix theory
Index of the de Rham complex	Example	Global analysis, analysis on manifolds
Relational structure	Definition	General algebraic systems
Homotopy	Definition	Algebraic topology
Hodges' superefficient estimator	Counterexample	Statistics
Homotopy hypothesis	Conjecture	Category theory; homological algebra
Martingale representation theorem	Theorem	Probability theory and stochastic processes
Quantum logic	Concept	Quantum theory
Permutation test	Concept	Statistics
Spherical mean transform	Definition	Integral transforms, operational calculus
Integral equation of the second kind	Definition	Integral equations
Catastrophe theory	Definition	Global analysis, analysis on manifolds
Inaccessible cardinal	Definition	Mathematical logic and foundations
List of simple Lie groups	Example	Topological groups, Lie groups
Modified Bessel functions	Concept	Special functions
Darboux's theorem on additive functions bounded on an interval	Theorem	Difference and functional equations
Quantile regression	Concept	Statistics
Theta function	Concept	Number theory
Green's function for the Laplacian	Definition	Potential theory
Von Neumann's theorem on self-adjoint extensions	Theorem	Operator theory
Conformal modulus	Concept	Functions of a complex variable
Integral quadratic form	Concept	Number theory
dg category	Definition	Category theory; homological algebra
Absolutely continuous measure	Definition	Measure and integration
t-structure	Concept	Category theory; homological algebra
Lagrange resolvent	Concept	Field theory and polynomials
Reeb vector field	Definition	Differential geometry
Mean curvature flow	Definition	Differential geometry
Phragmén–Lindelöf principle for subharmonic functions	Theorem	Potential theory
Symmetric decreasing rearrangement	Concept	Real functions
Whitney embedding theorem	Theorem	Manifolds and cell complexes
Projective determinacy	Concept	Mathematical logic and foundations
Local regression	Definition	Statistics
Garden of Eden theorem	Theorem	Dynamical systems and ergodic theory
Chain recurrence	Definition	Dynamical systems and ergodic theory
Closure operator	Concept	Order, lattices, ordered algebraic structures
Nilpotency class	Definition	Group theory and generalizations
Wavelet packet decomposition	Definition	Harmonic analysis on Euclidean spaces
Riemann zeta function as a series	Example	Sequences, series, summability
Poincaré asymptotic series	Concept	Approximations and expansions
Finite projective plane	Object	Geometry
Infinite product measure	Concept	Measure and integration
Sheafification	Concept	Category theory; homological algebra
Itô's lemma	Theorem	Probability theory and stochastic processes
Homology of a chain complex	Concept	Category theory; homological algebra
Holomorphic automorphisms of C^n	Concept	Several complex variables and analytic spaces
Harmonic functions on Riemannian manifolds	Definition	Potential theory
Stochastic geometry	Concept	Probability theory and stochastic processes
Pro-p group	Definition	Group theory and generalizations
Autoregressive model	Concept	Statistics
Hopf–Lax formula	Theorem	Partial differential equations
Cauchy matrix	Definition	Linear and multilinear algebra; matrix theory
Countably generated structure	Concept	General algebraic systems
Loop space	Concept	Algebraic topology
Weyl's law	Theorem	Partial differential equations
Associativity equation	Concept	Difference and functional equations
Simplex algorithm	Definition	Operations research, mathematical programming
Cancellation property	Definition	General algebraic systems
Holomorphic function of several variables	Definition	Several complex variables and analytic spaces
Nilradical	Definition	Commutative algebra
Representation of a Lie group	Definition	Topological groups, Lie groups
Non-Euclidean geometry	Definition	Geometry
Amalgamation property	Definition	Mathematical logic and foundations
Finite Hilbert transform	Definition	Integral transforms, operational calculus
Hypergraph	Definition	Combinatorics
Y transform	Concept	Integral transforms, operational calculus
Morse–Bott function	Definition	Manifolds and cell complexes
Inverse transform sampling	Theorem	Numerical analysis
Matrix Wiener–Hopf factorization	Theorem	Integral equations
Unconditional convergence	Concept	Sequences, series, summability
Weak mixing	Concept	Dynamical systems and ergodic theory
Harish-Chandra module	Concept	Topological groups, Lie groups
Backward difference operator	Definition	Difference and functional equations
Eberlein–Šmulian theorem	Theorem	Functional analysis
Space of convergent sequences c	Example	Functional analysis
Interval order	Definition	Order, lattices, ordered algebraic structures
Group von Neumann algebra	Concept	Topological groups, Lie groups
Relaxation oscillation	Concept	Ordinary differential equations
Jordan–Kinderlehrer–Otto scheme	Definition	Calculus of variations and optimal control; optimization
Poncelet–Steiner theorem	Theorem	Geometry
Horn hypergeometric series	Definition	Special functions
Linear logic	Concept	Mathematical logic and foundations
Free algebra	Concept	Associative rings and algebras
List of integral transforms	Concept	Integral transforms, operational calculus
Fourier–Mukai transform	Concept	Algebraic geometry
Hankel transform	Concept	Integral transforms, operational calculus
Lempert's theorem on convex domains	Theorem	Several complex variables and analytic spaces
Group cohomology	Definition	Group theory and generalizations
Parallel postulate	Fact	Geometry
Temperley–Lieb algebra	Definition	Associative rings and algebras
Born series	Concept	Quantum theory
Uniqueness of adjoints	Proposition	Category theory; homological algebra
Cofinal subset	Concept	Order, lattices, ordered algebraic structures
Rectifiable set	Definition	Measure and integration
Bulirsch–Stoer algorithm	Theorem	Numerical analysis
Hahn decomposition theorem	Theorem	Measure and integration
Transfinite diameter	Definition	Potential theory
Ziggurat algorithm	Theorem	Numerical analysis
Elliptic regularity	Theorem	Partial differential equations
Path algebra	Concept	Associative rings and algebras
Steinitz's theorem	Theorem	Convex and discrete geometry
Jordan–Brouwer separation theorem	Theorem	Algebraic topology
Irrational rotation	Example	Dynamical systems and ergodic theory
Abel function	Concept	Difference and functional equations
Wavelet packet decomposition	Concept	Harmonic analysis on Euclidean spaces
Étale morphism of rings	Definition	Commutative algebra
Least squares approximation	Concept	Approximations and expansions
Clausen function	Definition	Special functions
Bochner–Riesz means	Definition	Harmonic analysis on Euclidean spaces
Lattice of equational theories	Concept	General algebraic systems
Newtonian space	Definition	Functional analysis
Projective subspace	Concept	Geometry
Prüfer domain	Concept	Commutative algebra
Ehrenfeucht–Fraïssé game	Concept	Mathematical logic and foundations
Repair radii and villainy	Definition	Combinatorics
Point spectrum	Definition	Operator theory
Fredholm equation of the first kind	Concept	Integral equations
Iterative method	Concept	Numerical analysis
Pluriharmonic function	Definition	Several complex variables and analytic spaces
Poisson bracket	Concept	Differential geometry
Field of formal Laurent series	Definition	Commutative algebra
Generalized Fourier series	Definition	Harmonic analysis on Euclidean spaces
Chinese restaurant process	Example	Probability theory and stochastic processes
Classification of surfaces	Theorem	Manifolds and cell complexes
Regular category	Concept	Category theory; homological algebra
Holomorphic functions on compact complex manifolds are constant	Proposition	Several complex variables and analytic spaces
Lifting idempotents	Concept	Associative rings and algebras
Ohsawa–Takegoshi extension theorem	Theorem	Several complex variables and analytic spaces
Primitive ring	Definition	Associative rings and algebras
Geometric group theory	Concept	Group theory and generalizations
Monotone class theorem	Theorem	Measure and integration
Finite element exterior calculus	Concept	Numerical analysis
Balanced set	Concept	Functional analysis
Design of experiments	Concept	Statistics
Germ of a holomorphic function	Definition	Several complex variables and analytic spaces
Mellin convergence	Definition	Integral transforms, operational calculus
Generated subalgebra	Concept	General algebraic systems
Hankel contour integral for the gamma function	Theorem	Special functions
Beurling's theorem	Theorem	Operator theory
Method of multiple scales	Concept	Ordinary differential equations
Absorbing set	Definition	Functional analysis
Contravariant functor	Definition	Category theory; homological algebra
Matlis duality	Theorem	Commutative algebra
Fredholm index	Concept	Operator theory
Suspension	Definition	Algebraic topology
I-adic topology	Concept	Commutative algebra
Derived category of coherent sheaves	Concept	Algebraic geometry
Nichols algebra	Definition	Associative rings and algebras
Namioka--Phelps	Theorem	Functional analysis