Every idea

Ideas 19801–19934 of 19934.

Name	Kind	Subject
Ricci flow	Definition	Differential geometry
Horn clause	Definition	Mathematical logic and foundations
Inverse Fourier transform	Definition	Harmonic analysis on Euclidean spaces
Ideal MHD equations	Concept	Fluid mechanics
Johnson solid	Object	Geometry
Conway knot	Example	Manifolds and cell complexes
Schechter luminosity function	Concept	Astronomy and astrophysics
Bogoliubov theory of the weakly interacting Bose gas	Concept	Statistical mechanics, structure of matter
Inductance	Definition	Optics, electromagnetic theory
Hodge structure	Concept	Algebraic geometry
Debye length	Concept	Statistical mechanics, structure of matter
Flow network	Concept	Operations research, mathematical programming
Kármán–Howarth equation	Proposition	Fluid mechanics
Method of images	Concept	Potential theory
Non-Newtonian fluid	Definition	Fluid mechanics
Hungarian algorithm	Definition	Operations research, mathematical programming
Universal class	Concept	Mathematical logic and foundations
Forced convection	Definition	Fluid mechanics
Maximal subfield	Concept	Associative rings and algebras
Lie derivative	Definition	Differential geometry
Glen's flow law	Fact	Geophysics
Lefschetz number	Concept	Algebraic topology
L-infinity space	Concept	Functional analysis
K-theory	Concept	K-theory
Weak gravitational lensing	Concept	Astronomy and astrophysics
Complemented lattice	Concept	Order, lattices, ordered algebraic structures
Absolute continuity	Concept	Real functions
Seiberg–Witten theory	Definition	Quantum theory
Morley's trisector theorem	Theorem	Geometry
Projective space	Concept	Algebraic geometry
Pushforward measure	Definition	Measure and integration
Markov parameters and the Hankel matrix of a system	Definition	Systems theory; control
Faber's theorem on interpolation	Theorem	Approximations and expansions
Brown–Douglas–Fillmore theory	Concept	K-theory
Contact geometry of thermodynamics	Concept	Classical thermodynamics, heat transfer
Column generation	Definition	Operations research, mathematical programming
Proper equilibrium	Concept	Game theory, economics, finance, and other social and behavioral sciences
Input-to-state stability	Definition	Systems theory; control
Simply typed lambda calculus	Definition	Mathematical logic and foundations
Definable set	Definition	Mathematical logic and foundations
Zariski's multiplicity conjecture	Conjecture	Several complex variables and analytic spaces
Hindman's theorem	Theorem	Combinatorics
Mellin transform as a Fourier transform in logarithmic variables	Proposition	Integral transforms, operational calculus
Artinian ring	Definition	Commutative algebra
Partially well-ordered set	Definition	Order, lattices, ordered algebraic structures
Stone space	Concept	Order, lattices, ordered algebraic structures
Kernel density estimation	Concept	Statistics
Grothendieck spectral sequence	Theorem	Category theory; homological algebra
Open immersion	Definition	Algebraic geometry
Bilinear interpolation	Definition	Numerical analysis
Montel's theorem	Theorem	Functions of a complex variable
Topology generated by a family of seminorms	Concept	Functional analysis
Numerical linear algebra	Definition	Numerical analysis
Quiver	Definition	Associative rings and algebras
Essential supremum	Definition	Measure and integration
Arnold diffusion	Concept	Dynamical systems and ergodic theory
Partial difference equation	Definition	Difference and functional equations
Kodaira dimension	Concept	Algebraic geometry
Kleene star	Concept	Computer science
Langevin equation	Concept	Probability theory and stochastic processes
Injective resolution	Concept	Category theory; homological algebra
Sigma-compact space	Concept	General topology
Regular and singular points of an analytic set	Concept	Several complex variables and analytic spaces
Statistical convergence	Concept	Sequences, series, summability
No surjection from the positive integers onto the unit interval	Proposition	Mathematical logic and foundations
Drude model	Definition	Statistical mechanics, structure of matter
Nondeterministic finite automaton	Definition	Computer science
Thermal resistance	Definition	Classical thermodynamics, heat transfer
Birch and Swinnerton-Dyer conjecture	Conjecture	Number theory
Entanglement distillation	Concept	Quantum theory
Streamlines, streaklines and pathlines	Concept	Fluid mechanics
Local martingale	Definition	Probability theory and stochastic processes
Mason–Stothers theorem	Theorem	Number theory
Brachistochrone problem	Problem	Calculus of variations and optimal control; optimization
Weak Nullstellensatz	Theorem	Commutative algebra
Newton–Puiseux theorem	Theorem	Commutative algebra
Péclet number	Definition	Fluid mechanics
Maxwell stress tensor	Concept	Optics, electromagnetic theory
Quaternion algebra	Concept	Associative rings and algebras
Pareto efficiency	Definition	Game theory, economics, finance, and other social and behavioral sciences
Dynamic similarity	Concept	Fluid mechanics
A priori estimate	Definition	Partial differential equations
Cutting-plane method	Definition	Operations research, mathematical programming
f(R) gravity	Concept	Relativity and gravitational theory
Proof of the cancellation laws	Proof	Group theory and generalizations
Completion of a measure	Definition	Measure and integration
Hellinger–Toeplitz theorem	Theorem	Operator theory
Disjoint union topology	Concept	General topology
Absolute continuity of the Lebesgue integral	Proposition	Measure and integration
Theil index	Concept	Game theory, economics, finance, and other social and behavioral sciences
Biot–Savart law for vortex filaments	Proposition	Fluid mechanics
Lattice gauge theory	Definition	Quantum theory
Reduced scheme	Concept	Algebraic geometry
Divisible group	Concept	Group theory and generalizations
Maupertuis's principle	Theorem	Mechanics of particles and systems
Transitivity of integrality	Proposition	Commutative algebra
Bäcklund transform	Definition	Dynamical systems and ergodic theory
Khachiyan's theorem that linear programming is in P	Theorem	Operations research, mathematical programming
Riemann solver	Concept	Numerical analysis
Euler–Lagrange equation	Definition	Calculus of variations and optimal control; optimization
Category of small categories	Example	Category theory; homological algebra
Fundamental solution	Definition	Partial differential equations
Whitehead tower	Definition	Algebraic topology
Littelmann path model	Definition	Nonassociative rings and algebras
Boundary integral equation for the Dirichlet problem	Theorem	Potential theory
Riesz basis	Concept	Harmonic analysis on Euclidean spaces
Divide-and-conquer algorithm	Definition	Computer science
Levitzki radical	Definition	Associative rings and algebras
Biot number	Concept	Classical thermodynamics, heat transfer
Discrete valuation	Definition	Field theory and polynomials
Invariant mean	Concept	Abstract harmonic analysis
Height of a poset	Definition	Order, lattices, ordered algebraic structures
Degree of exactness of a quadrature rule	Concept	Numerical analysis
Iwasawa decomposition	Theorem	Nonassociative rings and algebras
Thom–Boardman singularities	Definition	Manifolds and cell complexes
Pariah groups	Concept	Group theory and generalizations
hp-FEM	Concept	Numerical analysis
Radial distribution function	Definition	Statistical mechanics, structure of matter
Branch and bound	Concept	Operations research, mathematical programming
Elliptic gamma function	Definition	Special functions
Spence signaling model	Definition	Game theory, economics, finance, and other social and behavioral sciences
Chapman–Jouguet condition	Proposition	Fluid mechanics
Lane–Emden equation	Definition	Partial differential equations
Residue calculus for Laplace inversion	Definition	Integral transforms, operational calculus
Free magma	Example	General algebraic systems
Orderable group	Definition	Group theory and generalizations
Inverse mean curvature flow	Definition	Differential geometry
Teichmüller space	Concept	Functions of a complex variable
Continuous multiplication	Concept	Topological groups, Lie groups
Étale cohomology	Definition	Algebraic geometry
Stein–Tomas restriction theorem	Theorem	Harmonic analysis on Euclidean spaces
Obstruction theory	Concept	Algebraic topology
Critical path method	Definition	Operations research, mathematical programming
Heisenberg group	Example	Topological groups, Lie groups