Every idea

Ideas 20401–20550 of 21839.

Name	Kind	Subject
Exchangeable random variables	Definition	Probability theory and stochastic processes
Canonical coordinates	Concept	Mechanics of particles and systems
Function field	Concept	Field theory and polynomials
Empirical process	Concept	Probability theory and stochastic processes
Quillen adjunction	Definition	Category theory; homological algebra
Coefficient of determination	Definition	Statistics
Cohomological dimension of a field	Definition	Field theory and polynomials
Prime end	Definition	Functions of a complex variable
Grunsky matrix	Concept	Functions of a complex variable
Potential flow around a circular cylinder	Example	Fluid mechanics
Mathematical optimization	Definition	Operations research, mathematical programming
Pentagon identity	Fact	Category theory; homological algebra
Theta transformation formula	Theorem	Number theory
Equidistribution modulo one	Concept	Number theory
Hilbert's theorem on the hyperbolic plane	Theorem	Differential geometry
Proof that a product of compact sets is compact by the tube lemma	Proof	General topology
Monte Carlo methods in finance	Definition	Game theory, economics, finance, and other social and behavioral sciences
Equilibrium problem with an external field	Problem	Potential theory
Schwarz triangle function	Concept	Special functions
Cosmological perturbation theory	Concept	Relativity and gravitational theory
AKS primality test	Theorem	Number theory
Associated bundle	Definition	Algebraic topology
Levi decomposition	Theorem	Nonassociative rings and algebras
Triangle removal lemma	Lemma	Combinatorics
Classical field theory	Definition	Mechanics of particles and systems
Two-way finite automaton	Definition	Computer science
Bounded gaps between primes	Theorem	Number theory
Subordinate connective	Concept
Néron–Severi group	Concept	Algebraic geometry
Hyperbolic conservation law	Concept	Partial differential equations
Proof that abelian simple groups have prime order	Proof	Group theory and generalizations
Substitution	Definition	Mathematical logic and foundations
Implied volatility	Concept	Game theory, economics, finance, and other social and behavioral sciences
Admissible decision rule	Definition	Statistics
Torus as a group	Example	Topological groups, Lie groups
Sumset	Concept	Number theory
Proof of the rank–nullity theorem by extending a basis of the kernel	Proof	Linear and multilinear algebra; matrix theory
Hertzian contact stress	Theorem	Mechanics of deformable solids
Proof that the symmetric group on five or more letters is not solvable	Proof	Group theory and generalizations
Fredholm module	Definition	K-theory
Factorization of polynomials over finite fields	Concept	Number theory
Hartmann number	Definition	Fluid mechanics
Fin heat transfer	Concept	Classical thermodynamics, heat transfer
Hemicontinuity	Concept	General topology
De la Vallée Poussin lower bound	Theorem	Approximations and expansions
Proof of the anticommutativity of the cross product	Proof	Linear and multilinear algebra; matrix theory
PSPACE	Definition	Computer science
Convex polytope	Definition	Convex and discrete geometry
Dirac equation	Concept	Partial differential equations
Law (mathematics)	Proposition
Dehn twist	Definition	Manifolds and cell complexes
Branch point	Concept	Functions of a complex variable
Polynomial operation	Concept	General algebraic systems
Nuclear operator	Concept	Operator theory
Nesbitt's inequality	Proposition	Real functions
Unimodular group	Definition	Topological groups, Lie groups
Propositional connective	Concept
Thermodynamic system	Definition	Classical thermodynamics, heat transfer
Contraction semigroup	Concept	Operator theory
Proof that every real number has a decimal expansion, with digits from the floor	Proof	Number theory
Reduced mass	Definition	Mechanics of particles and systems
Brunt–Väisälä frequency	Concept	Fluid mechanics
Fredholm's theorem	Theorem	Integral equations
Optical soliton	Concept	Optics, electromagnetic theory
State-transition matrix	Definition	Ordinary differential equations
Hyperbolic partial differential equation	Definition	Partial differential equations
Intuitionism	Concept	Mathematical logic and foundations
Proof of Menelaus's theorem by a linear function	Proof	Geometry
Hochschild homology	Definition	Associative rings and algebras
Goodstein's theorem	Theorem	Mathematical logic and foundations
Pseudo-differential operator	Definition	Partial differential equations
ADM energy	Concept	Relativity and gravitational theory
Threshold theorem of epidemiology	Theorem	Biology and other natural sciences
ZPP	Definition	Computer science
Montessus de Ballore's theorem	Theorem	Approximations and expansions
Laplace transform method for convolution equations	Definition	Integral equations
Error threshold	Proposition	Biology and other natural sciences
Ideal completion	Definition	Order, lattices, ordered algebraic structures
Quasi-geostrophic equations	Definition	Fluid mechanics
Hodge index theorem	Theorem	Algebraic geometry
Finiteness of associated primes	Theorem	Commutative algebra
Pseudovariety	Concept	General algebraic systems
Schwarz reflection principle for harmonic functions	Theorem	Potential theory
Graph reconstruction conjecture	Conjecture	Combinatorics
Paradoxical decomposition	Concept	Abstract harmonic analysis
Time-variant system	Definition	Systems theory; control
Magnetic field	Concept	Optics, electromagnetic theory
Descending chain condition	Definition	Order, lattices, ordered algebraic structures
Proof of the fundamental theorem of calculus	Proof	Real functions
Existence and uniqueness for second-order linear initial value problems	Theorem	Ordinary differential equations
Method of fundamental solutions	Definition	Numerical analysis
Separable degree	Definition	Field theory and polynomials
Cyclic term theorem	Theorem	General algebraic systems
Shilov boundary	Definition	Functional analysis
Herd immunity threshold	Proposition	Biology and other natural sciences
Hotelling's T-squared distribution	Concept	Statistics
Order parameter	Concept	Statistical mechanics, structure of matter
Amalgamation property	Concept	Mathematical logic and foundations
Transverse isotropy	Concept	Mechanics of deformable solids
Low-discrepancy sequence	Concept	Number theory
Green's function of a Markov process	Concept	Probability theory and stochastic processes
Hidden-variable theory	Definition	Quantum theory
Jeans equations	Proposition	Astronomy and astrophysics
Manin conjecture	Conjecture	Algebraic geometry
System of parameters	Definition	Commutative algebra
Abstraction principle	Concept
Hadamard's lemma	Lemma	Real functions
Heilbronn triangle problem	Problem	Convex and discrete geometry
Dirichlet process	Concept	Probability theory and stochastic processes
Jordan–Schur theorem	Theorem	Group theory and generalizations
Homology with coefficients	Concept	Algebraic topology
Weyl–Titchmarsh theory	Concept	Ordinary differential equations
Proof that the chromatic number of a complete bipartite graph is 2	Proof	Combinatorics
Cardinal points of an optical system	Concept	Optics, electromagnetic theory
Proof of the well-ordering theorem from Zorn's lemma	Proof	Mathematical logic and foundations
Lambert's cosine law	Proposition	Classical thermodynamics, heat transfer
Three-dimensional gravity and BTZ black hole	Example	Relativity and gravitational theory
Classification of simple Lie superalgebras	Theorem	Nonassociative rings and algebras
Channel capacity of a quantum channel	Definition	Quantum theory
Proof that a series of nonnegative terms converges iff its partial sums are bounded	Proof	Sequences, series, summability
Rational variety	Concept	Algebraic geometry
Coroot	Concept	Nonassociative rings and algebras
Wess–Zumino model	Example	Quantum theory
P	Definition	Computer science
Linear-fractional programming	Concept	Operations research, mathematical programming
Conformal geometric algebra	Definition	Linear and multilinear algebra; matrix theory
Lebesgue integral	Definition	Measure and integration
Multiplicative decomposition of the deformation gradient	Definition	Mechanics of deformable solids
Well-powered category	Concept	Category theory; homological algebra
Diffusion-limited aggregation	Example	Statistical mechanics, structure of matter
Kruskal's tree theorem	Theorem	Combinatorics
Gromov–Witten invariant	Concept	Algebraic geometry
Blaschke–Lebesgue theorem	Theorem	Convex and discrete geometry
Cardinal function	Concept	General topology
Proper time	Definition	Relativity and gravitational theory
Semiprimary ring	Concept	Associative rings and algebras
Supporting hyperplane	Definition	Convex and discrete geometry
Disk algebra	Definition	Functional analysis
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
Stratified	Concept
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