Every idea

Ideas 16651–16800 of 19838.

Name	Kind	Subject
K1 of a Euclidean domain	Example	K-theory
Dimensionless numbers in fluid mechanics	Concept	Fluid mechanics
Bitonic sorter	Definition	Computer science
Optimal control	Concept	Calculus of variations and optimal control; optimization
Alexander's theorem on proper self-maps of the ball	Theorem	Several complex variables and analytic spaces
General solution of a second order equation with complex characteristic roots	Theorem	Ordinary differential equations
Differential field	Definition	Field theory and polynomials
Substitution tiling	Definition	Dynamical systems and ergodic theory
Primal algebra	Definition	General algebraic systems
Nijenhuis tensor	Concept	Differential geometry
Special Jordan algebra	Concept	Nonassociative rings and algebras
Omega-complete partial order	Concept	Order, lattices, ordered algebraic structures
Chandrasekhar–Friedman–Schutz instability	Theorem	Astronomy and astrophysics
Topological data analysis	Definition	Statistics
4-manifold	Definition	Manifolds and cell complexes
Mayer f-function	Concept	Statistical mechanics, structure of matter
Fourier series on the torus	Definition	Harmonic analysis on Euclidean spaces
Nerve theorem	Theorem	Algebraic topology
Variable-mass system	Definition	Mechanics of particles and systems
The alternating group A3 is normal in S3	Example	Group theory and generalizations
Sphere packing	Definition	Convex and discrete geometry
Gelfand's spectral radius formula	Theorem	Functional analysis
Reductive Lie algebra	Concept	Nonassociative rings and algebras
Recurrence relations for Bessel functions	Proposition	Special functions
Sequential equilibrium	Concept	Game theory, economics, finance, and other social and behavioral sciences
Fourier inversion theorem	Theorem	Harmonic analysis on Euclidean spaces
Computational fluid dynamics	Concept	Fluid mechanics
Newtonian fluid	Concept	Fluid mechanics
Monotone cubic interpolation	Theorem	Numerical analysis
Doléans-Dade exponential	Definition	Probability theory and stochastic processes
Hamiltonian optics	Concept	Optics, electromagnetic theory
Direct collocation	Concept	Calculus of variations and optimal control; optimization
Verification theorem	Theorem	Calculus of variations and optimal control; optimization
Barbier's theorem	Theorem	Convex and discrete geometry
Free distributive lattice	Concept	Order, lattices, ordered algebraic structures
Zimmer program	Definition	Dynamical systems and ergodic theory
Gårding's inequality	Theorem	Partial differential equations
Green's function of the ball	Example	Potential theory
Baum–Welch algorithm	Definition	Statistics
Baouendi–Trèves approximation theorem	Theorem	Several complex variables and analytic spaces
Modular curve	Concept	Number theory
Ambrose–Singer theorem	Theorem	Differential geometry
n-sphere	Object	Manifolds and cell complexes
Maximum principle for harmonic functions	Theorem	Potential theory
Rapidity	Concept	Relativity and gravitational theory
Lamb waves	Definition	Mechanics of deformable solids
Parker instability	Definition	Astronomy and astrophysics
Coefficient of performance	Definition	Classical thermodynamics, heat transfer
System of imprimitivity	Definition	Topological groups, Lie groups
Right adjoints preserve limits	Theorem	Category theory; homological algebra
Mather's stability theorem	Theorem	Global analysis, analysis on manifolds
Discrete Poisson equation	Definition	Difference and functional equations
Descartes' rule of signs	Theorem	Real functions
Orbital angular momentum of light	Concept	Optics, electromagnetic theory
Gorenstein ring	Concept	Commutative algebra
Hodges–Lehmann estimator	Concept	Statistics
Plane stress	Definition	Mechanics of deformable solids
Topological modular forms	Definition	Algebraic topology
Turing reduction	Definition	Mathematical logic and foundations
Prim's algorithm	Definition	Combinatorics
Steklov eigenvalue problem	Problem	Partial differential equations
EXPTIME	Definition	Computer science
Nelder–Mead method	Concept	Operations research, mathematical programming
Fractional calculus	Concept	Real functions
Energy release rate	Definition	Mechanics of deformable solids
Periodic point	Concept	Dynamical systems and ergodic theory
Trigonometric integrals	Definition	Special functions
Lattice congruence	Concept	Order, lattices, ordered algebraic structures
E-infinity operad	Concept	Algebraic topology
Isochoric process	Definition	Classical thermodynamics, heat transfer
Projective transformation	Definition	Geometry
Hammerstein integral equation	Concept	Integral equations
Lagrangian density	Definition	Mechanics of particles and systems
Upper critical dimension	Definition	Statistical mechanics, structure of matter
Ordered geometry	Concept	Geometry
Generator of a semigroup	Definition	Operator theory
Stable theory	Concept	Mathematical logic and foundations
Electrical network	Concept	Potential theory
Fenchel conjugate	Concept	Convex and discrete geometry
Semenov's theory of thermal explosion	Definition	Classical thermodynamics, heat transfer
Linear program in standard form	Concept	Operations research, mathematical programming
Inner function	Definition	Functions of a complex variable
Equivariant index theorem	Theorem	Global analysis, analysis on manifolds
Muckenhoupt weights	Concept	Harmonic analysis on Euclidean spaces
List decoding	Concept	Information and communication theory, circuits
Cobordism	Concept	Manifolds and cell complexes
Multivariate division algorithm	Concept	Commutative algebra
Young's modulus	Concept	Mechanics of deformable solids
Thermodynamic potential	Definition	Classical thermodynamics, heat transfer
State function	Concept	Classical thermodynamics, heat transfer
Magnetohydrodynamics	Concept	Fluid mechanics
Residuated mapping	Definition	Order, lattices, ordered algebraic structures
Neville theta functions	Definition	Special functions
Mindlin–Reissner plate theory	Definition	Mechanics of deformable solids
q-exponential	Concept	Combinatorics
Monodromy of the hypergeometric equation	Concept	Special functions
Rational difference equation	Concept	Difference and functional equations
Bruhat decomposition	Theorem	Group theory and generalizations
Divided differences	Definition	Numerical analysis
Lebesgue's universal covering problem	Problem	Convex and discrete geometry
Wald test	Definition	Statistics
Shephard's lemma	Lemma	Game theory, economics, finance, and other social and behavioral sciences
Outer function	Definition	Functions of a complex variable
Filtering problem	Problem	Probability theory and stochastic processes
Pontryagin–Thom construction	Definition	Manifolds and cell complexes
Maximum cut	Problem	Operations research, mathematical programming
Szpilrajn extension theorem	Theorem	Order, lattices, ordered algebraic structures
Terzaghi's principle of effective stress	Fact	Mechanics of deformable solids
Pointed space	Concept	Algebraic topology
EXPTIME	Concept	Computer science
Morse theory on Hilbert manifolds	Concept	Global analysis, analysis on manifolds
PSPACE	Concept	Computer science
Bilateral Z-transform	Definition	Integral transforms, operational calculus
Spectral risk measure	Definition	Game theory, economics, finance, and other social and behavioral sciences
Fourier transform on finite groups	Definition	Abstract harmonic analysis
Loschmidt's paradox	Problem	Statistical mechanics, structure of matter
Surface plasmon polariton	Definition	Optics, electromagnetic theory
Semidirect product of Lie algebras	Concept	Nonassociative rings and algebras
Chomsky–Schützenberger representation theorem	Theorem	Computer science
Cayley–Dickson construction	Concept	Nonassociative rings and algebras
Cauchy momentum equation	Theorem	Mechanics of deformable solids
Degree of a projective variety	Definition	Algebraic geometry
Lie-admissible algebra	Definition	Nonassociative rings and algebras
Factorization system	Definition	Category theory; homological algebra
Integral quadratic form	Definition	Number theory
Hölder summation	Definition	Sequences, series, summability
Reaction–diffusion system	Concept	Partial differential equations
HNN extension	Definition	Group theory and generalizations
Error-correcting code	Concept	Information and communication theory, circuits
Heisenberg picture	Concept	Quantum theory
Expansive homeomorphism	Concept	Dynamical systems and ergodic theory
Abian–Brown theorem	Theorem	Order, lattices, ordered algebraic structures
Bicategory	Concept	Category theory; homological algebra
Fractional integration	Definition	Harmonic analysis on Euclidean spaces
Tautological one-form	Definition	Differential geometry
Learning with errors	Problem	Information and communication theory, circuits
Kawamata–Viehweg vanishing theorem	Theorem	Algebraic geometry
Integral geometry	Concept	Convex and discrete geometry
Ring of differential operators	Definition	Associative rings and algebras
Langevin equation	Definition	Probability theory and stochastic processes
Lévy–Prokhorov metric	Definition	Probability theory and stochastic processes
Direct limit	Definition	Category theory; homological algebra
Algebraic statistics	Concept	Statistics
Möbius–Kantor configuration	Example	Combinatorics
Square wave	Example	Harmonic analysis on Euclidean spaces
Gerstenhaber algebra	Definition	Nonassociative rings and algebras
Faithful module	Concept	Associative rings and algebras
Picard–Vessiot extension	Concept	Field theory and polynomials
Sheaf	Concept	General topology
Saddle-node bifurcation	Definition	Ordinary differential equations