Every idea

Ideas 7951–8100 of 10181.

Name	Kind	Subject
Projective hierarchy	Definition	Mathematical logic and foundations
Closed operator	Definition	Operator theory
Complex measure	Concept	Measure and integration
Kodaira vanishing theorem	Theorem	Algebraic geometry
Site	Concept	Category theory; homological algebra
de Branges space	Concept	Functional analysis
Adele ring	Definition	Number theory
Post's theorem	Theorem	Mathematical logic and foundations
Krein–Smulian theorem	Theorem	Functional analysis
Relatively free algebra	Concept	General algebraic systems
Nil ideal	Concept	Associative rings and algebras
Hyperfinite type II1 factor	Object	Functional analysis
Friedrichs extension	Definition	Operator theory
Matrix congruence	Definition	Linear and multilinear algebra; matrix theory
Symplectic integrator	Definition	Numerical analysis
Coupling from the past	Concept	Numerical analysis
Abelian differential	Concept	Functions of a complex variable
Gaussian measure	Concept	Measure and integration
Absolutely continuous measure	Concept	Measure and integration
Schwarz reflection principle	Theorem	Functions of a complex variable
Coalgebra	Definition	Associative rings and algebras
Hölder space	Concept	Functional analysis
Harnack's principle	Theorem	Potential theory
Measure space	Concept	Measure and integration
Character table	Concept	Group theory and generalizations
Higher-order logic	Concept	Mathematical logic and foundations
Maurer–Cartan form	Concept	Topological groups, Lie groups
Hilbert's program	Problem	Mathematical logic and foundations
G2 manifold	Concept	Differential geometry
Additive combinatorics	Definition	Number theory
Linearly ordered group	Concept	Order, lattices, ordered algebraic structures
Nerve of a cover	Definition	Algebraic topology
Splitting field of a central simple algebra	Definition	Associative rings and algebras
Operator monotone function	Definition	Operator theory
Propagation of singularities	Theorem	Partial differential equations
Baire space of sequences	Object	General topology
Pseudo algebraically closed field	Definition	Field theory and polynomials
Strict total order	Concept	Order, lattices, ordered algebraic structures
Elementary equivalence	Concept	Mathematical logic and foundations
Strict hyperbolicity	Concept	Partial differential equations
Lie's theorems on transformation groups	Theorem	Topological groups, Lie groups
Vector bundle	Concept	Algebraic geometry
Hankel operator	Concept	Operator theory
Tensor algebra	Concept	Linear and multilinear algebra; matrix theory
Surface	Definition	Manifolds and cell complexes
Burgers' equation	Definition	Partial differential equations
Kervaire invariant	Concept	Algebraic topology
Zassenhaus neighbourhood	Definition	Topological groups, Lie groups
Singular function	Concept	Real functions
Complete atomic Boolean algebra	Concept	Order, lattices, ordered algebraic structures
Turing degree	Concept	Mathematical logic and foundations
Queueing theory	Concept	Probability theory and stochastic processes
Topological group	Definition	Topological groups, Lie groups
Slice knot	Concept	Manifolds and cell complexes
Chain complex	Definition	Category theory; homological algebra
Local solvability	Concept	Partial differential equations
Wirtinger presentation	Theorem	Manifolds and cell complexes
Weak topology	Concept	Functional analysis
Algebraic K-theory of schemes	Definition	K-theory
Grothendieck–Lefschetz trace formula	Theorem	Algebraic geometry
Lie's third theorem	Theorem	Topological groups, Lie groups
Margulis lemma	Theorem	Differential geometry
Adjoint representation of a Lie group	Concept	Topological groups, Lie groups
Smooth four-dimensional Poincaré conjecture	Conjecture	Manifolds and cell complexes
Characterizations of Galois extensions	Theorem	Field theory and polynomials
Higman embedding theorem	Theorem	Group theory and generalizations
Group law on an elliptic curve	Concept	Algebraic geometry
Parallel transport	Definition	Differential geometry
Train track	Definition	Manifolds and cell complexes
Cartan–Eilenberg resolution	Definition	Category theory; homological algebra
Pitchfork bifurcation	Concept	Ordinary differential equations
Uniform structure of a topological group	Concept	Topological groups, Lie groups
Littlewood conjecture	Conjecture	Number theory
Differential graded algebra	Definition	Associative rings and algebras
Octahedral axiom	Concept	Category theory; homological algebra
Lorentz's characterization of almost convergence	Theorem	Sequences, series, summability
Local homomorphism	Concept	Commutative algebra
Kadomtsev–Petviashvili equation	Concept	Partial differential equations
Positive operator	Definition	Operator theory
Nilpotent operator	Definition	Operator theory
Homotopy group	Concept	Algebraic topology
Group homology	Definition	Group theory and generalizations
S-finite measure	Concept	Measure and integration
Developable surface	Definition	Differential geometry
Turing reduction	Concept	Mathematical logic and foundations
Mean curvature	Concept	Differential geometry
Löwner's theorem	Theorem	Operator theory
Symmetric space	Concept	Differential geometry
Chern class	Concept	Algebraic geometry
Tucker's lemma	Lemma	Combinatorics
Laplace–Beltrami operator	Definition	Global analysis, analysis on manifolds
Symmetric function	Concept	Combinatorics
Combinatorial design	Concept	Combinatorics
Frobenius reciprocity	Theorem	Group theory and generalizations
Natural deduction	Definition	Mathematical logic and foundations
Minkowski functional	Concept	Functional analysis
Double series	Concept	Sequences, series, summability
Motzkin number	Concept	Combinatorics
Serre fibration	Concept	Algebraic topology
Pseudo-element	Definition	Category theory; homological algebra
Symmetric algebra	Concept	Linear and multilinear algebra; matrix theory
Word problem for groups	Problem	Group theory and generalizations
Muirhead's inequality	Theorem	Real functions
Discrete spectrum	Definition	Operator theory
Choquet theory	Definition	Functional analysis
Well-quasi-ordering	Definition	Order, lattices, ordered algebraic structures
Recurrence and transience of states	Concept	Probability theory and stochastic processes
Comma category	Concept	Category theory; homological algebra
Derived category	Definition	Category theory; homological algebra
Multiplicative set	Definition	Commutative algebra
Skew group ring	Concept	Associative rings and algebras
Sierpiński carpet	Example	General topology
Inverse problem	Concept	Partial differential equations
Levi-Civita connection	Definition	Differential geometry
State on a C*-algebra	Definition	Functional analysis
Convergence of an infinite product	Concept	Sequences, series, summability
Commutative algebra over a ring	Definition	Commutative algebra
Residual set	Definition	General topology
Shelf	Concept	Group theory and generalizations
CW approximation	Theorem	Algebraic topology
Laguerre–Pólya class	Definition	Functions of a complex variable
Bishop–Phelps theorem	Theorem	Functional analysis
Gateaux derivative	Definition	Functional analysis
Hedetniemi's conjecture	Counterexample	Combinatorics
Absolute summability	Definition	Sequences, series, summability
Torsion-free group	Concept	Group theory and generalizations
Axiom of determinacy	Concept	Mathematical logic and foundations
Wave front set	Definition	Partial differential equations
Content	Concept	Measure and integration
Algebra of sets	Concept	Measure and integration
Contraction semigroup	Definition	Operator theory
Modular function	Definition	Topological groups, Lie groups
Bruhat decomposition of a Lie group	Theorem	Topological groups, Lie groups
Antipode	Concept	Associative rings and algebras
Homotopy group	Definition	Algebraic topology
Amenable group	Definition	Abstract harmonic analysis
Kneser's theorem on solution sets	Theorem	Ordinary differential equations
Quasicircle	Definition	Functions of a complex variable
Mahlo cardinal	Definition	Mathematical logic and foundations
Absolute Galois group	Concept	Field theory and polynomials
Universal Horn class	Definition	Mathematical logic and foundations
Christodoulou–Klainerman stability of Minkowski space	Theorem	Relativity and gravitational theory
Motzkin number	Definition	Combinatorics
Hopfian group	Concept	Group theory and generalizations
Regular conditional probability	Concept	Probability theory and stochastic processes
Ax–Kochen theorem	Theorem	Field theory and polynomials
Measurable function	Definition	Measure and integration
Absorbing element	Concept	General algebraic systems
Lifting idempotents	Definition	Associative rings and algebras
Lie derivative	Concept	Differential geometry