Every idea

Ideas 21001–21150 of 21839.

Name	Kind	Subject
Ambiguity function	Definition	Information and communication theory, circuits
Discrete Dirichlet problem	Problem	Potential theory
International Geomagnetic Reference Field	Object	Geophysics
Kauffman bracket	Definition	Manifolds and cell complexes
Coleman–Mandula theorem	Theorem	Quantum theory
Theorema Egregium	Theorem	Differential geometry
Developable surface	Concept	Differential geometry
Effective temperature	Definition	Astronomy and astrophysics
Circle average	Definition	Potential theory
Likelihood-ratio test	Concept	Statistics
Hamilton's principal function	Concept	Mechanics of particles and systems
Perturbation theory in quantum mechanics	Definition	Quantum theory
Rellich–Kondrachov theorem	Theorem	Functional analysis
Bland's rule	Concept	Operations research, mathematical programming
Multiplication theorem	Theorem	Special functions
Ordinary least squares	Concept	Statistics
Arithmetic Fuchsian group	Concept
Local asymptotic normality	Definition	Statistics
Planetary migration	Concept	Astronomy and astrophysics
Oscillation of a function	Definition	Real functions
Bochner–Martinelli formula	Theorem	Several complex variables and analytic spaces
Site	Definition	Category theory; homological algebra
Minimalism	Concept
Bochner's tube theorem	Theorem	Several complex variables and analytic spaces
Stably free module	Concept	K-theory
Bredon cohomology	Concept	Algebraic topology
Capillary wave	Definition	Fluid mechanics
Log mean temperature difference	Definition	Classical thermodynamics, heat transfer
Harish-Chandra isomorphism	Theorem	Nonassociative rings and algebras
Frequentist inference	Definition	Statistics
Incidence matrix	Definition	Combinatorics
Harnack's inequality	Theorem	Potential theory
Gumm terms	Definition	General algebraic systems
Restricted Lie algebra	Definition	Nonassociative rings and algebras
Kappa mechanism	Definition	Astronomy and astrophysics
Proof of the integral of 1/x	Proof	Real functions
Extensional function	Concept
Synchronization of chaos	Concept	Ordinary differential equations
Proof that continuity is equivalent to sequential continuity in metric spaces	Proof	General topology
Proof that the Cauchy product of absolutely convergent series converges absolutely to the product	Proof	Sequences, series, summability
Nonassociative ring	Concept	Nonassociative rings and algebras
Proof that the curl of a gradient is zero	Proof	Real functions
Chevalley group	Concept	Group theory and generalizations
Integer factorization	Problem	Number theory
Affine arithmetic	Concept	Numerical analysis
Approximation theory	Concept	Approximations and expansions
Proof that pi is greater than 3 by the alternating series estimate	Proof	Number theory
Subfactor	Definition	Functional analysis
1 + 1 + 1 + 1 + ⋯	Example	Sequences, series, summability
Verma module	Definition	Nonassociative rings and algebras
Equation of state	Concept	Classical thermodynamics, heat transfer
Baker–Gammel–Wills conjecture	Conjecture	Approximations and expansions
Hurwitz zeta function	Definition	Number theory
Energy cascade	Concept	Fluid mechanics
Locally finite measure	Concept	Measure and integration
Finitely presented module	Definition	Commutative algebra
Commutant	Definition	Functional analysis
Statics	Definition	Mechanics of particles and systems
Functional inequality	Concept	Difference and functional equations
Reversible process	Definition	Classical thermodynamics, heat transfer
Shamir's secret sharing	Definition	Information and communication theory, circuits
Chern–Connes character	Definition	Functional analysis
Underactuated system	Definition	Mechanics of particles and systems
Rigorous coupled-wave analysis	Definition	Optics, electromagnetic theory
Proof of the product formula for the generating function of a sum of independent random variables	Proof	Probability theory and stochastic processes
Artinian module	Concept	Associative rings and algebras
Hahn series	Concept	Commutative algebra
Bessel polynomials	Definition	Special functions
Proof that slopes of a convex function are increasing	Proof	Real functions
BGK collision operator	Concept	Statistical mechanics, structure of matter
Taylor microscale	Definition	Fluid mechanics
Observability	Definition	Systems theory; control
Coherent risk measure	Concept	Game theory, economics, finance, and other social and behavioral sciences
Diagonally dominant matrix	Definition	Linear and multilinear algebra; matrix theory
Free boundary problem	Problem	Partial differential equations
Controllability	Definition	Systems theory; control
Likelihood principle	Axiom	Statistics
Model complete theory	Concept	Mathematical logic and foundations
Functional differential equation	Definition	Ordinary differential equations
Nevanlinna parametrization of solutions	Theorem	Integral transforms, operational calculus
Koszul algebra	Definition	Associative rings and algebras
Helioseismology	Definition	Astronomy and astrophysics
Kolmogorov automorphism	Concept	Dynamical systems and ergodic theory
Descriptive complexity theory	Concept	Computer science
Integro-differential equation	Concept	Integral equations
Adapted process	Concept	Probability theory and stochastic processes
Octonion algebra	Definition	Nonassociative rings and algebras
DeGroot learning	Concept	Game theory, economics, finance, and other social and behavioral sciences
Euler angles	Definition	Mechanics of particles and systems
Order of an entire function	Definition	Functions of a complex variable
Convex body	Definition	Convex and discrete geometry
Fluctuation–dissipation theorem	Theorem	Statistical mechanics, structure of matter
Tarski's undefinability theorem	Theorem	Mathematical logic and foundations
Dundas–Goodwillie–McCarthy theorem	Theorem	K-theory
Michell structures	Example	Mechanics of deformable solids
Elastic wave scattering	Concept	Mechanics of deformable solids
Three-term recurrence for orthogonal polynomials	Theorem	Harmonic analysis on Euclidean spaces
K2 and the Brauer group	Proposition	K-theory
Gaussian binomial coefficient	Concept	Combinatorics
Transmission line	Concept	Optics, electromagnetic theory
Nonlinear approximation	Concept	Approximations and expansions
Osterwalder–Schrader reconstruction theorem	Theorem	Quantum theory
Curse of dimensionality	Concept	Numerical analysis
Axiomatic potential theory	Concept	Potential theory
Nome	Concept	Special functions
Lambert summation	Definition	Sequences, series, summability
Proof that sums and products of continuous functions are continuous	Proof	Real functions
Schützenberger's theorem on star-free languages	Theorem	Computer science
Ruin theory	Concept	Game theory, economics, finance, and other social and behavioral sciences
Ramsey's theorem for colourings of s-subsets with several colours	Theorem	Combinatorics
Proof of the classification of isometries of the plane	Proof	Geometry
Celestial coordinate system	Concept	Astronomy and astrophysics
Weyl group	Concept	Nonassociative rings and algebras
Fuchsian equation	Definition	Ordinary differential equations
Compact quantum group	Definition	Functional analysis
Zeta-regularized determinant	Concept	Global analysis, analysis on manifolds
Annihilator duality	Theorem	Abstract harmonic analysis
Product order	Definition	Order, lattices, ordered algebraic structures
Nevanlinna characteristic	Concept	Functions of a complex variable
Isochoric process	Concept	Classical thermodynamics, heat transfer
Competitive equilibrium	Concept	Game theory, economics, finance, and other social and behavioral sciences
Omega	Concept
Proof that the determinant of a linear map does not depend on the basis	Proof	Linear and multilinear algebra; matrix theory
Mirror descent	Definition	Operations research, mathematical programming
Expansion in spherical harmonics	Theorem	Potential theory
Proof of Lucas's theorem by generating functions	Proof	Number theory
Time-optimal control	Problem	Calculus of variations and optimal control; optimization
Classifying topos	Definition	Category theory; homological algebra
Euler free nutation	Definition	Mechanics of particles and systems
Mellin transform of a dilation	Proposition	Integral transforms, operational calculus
Crystal plasticity	Concept	Mechanics of deformable solids
Quasi-everywhere	Definition	Potential theory
Vaught conjecture	Conjecture	Mathematical logic and foundations
Clenshaw–Curtis quadrature	Definition	Numerical analysis
Mersenne Twister	Object	Numerical analysis
Continuous and residual spectrum	Concept	Operator theory
Simplicial polytope	Concept	Convex and discrete geometry
Worm-like chain	Example	Statistical mechanics, structure of matter
Proof that every vector space has a basis, by Zorn's lemma	Proof	Linear and multilinear algebra; matrix theory
Lieb–Liniger model	Example	Statistical mechanics, structure of matter
Surreal number	Object	Order, lattices, ordered algebraic structures
Valuation ring	Definition	Commutative algebra
d'Alembert's formula	Theorem	Partial differential equations
Burke's theorem	Theorem	Probability theory and stochastic processes
Twistor theory	Concept	Several complex variables and analytic spaces
Grand potential	Definition	Classical thermodynamics, heat transfer
Black hole	Definition	Relativity and gravitational theory
Topology of uniform convergence	Concept	General topology
Jacobi field	Definition	Differential geometry
Deformation retract	Definition	General topology