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PlanetMath Encyclopedia

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0 - 5 entries

1 - 12 entries

2 - 22 entries

3 - 10 entries

4 - 6 entries

5 - 4 entries

6 - 2 entries

9 - 2 entries

A - 1104 entries

B - 678 entries

C - 2221 entries

D - 918 entries

E - 907 entries

F - 821 entries

G - 659 entries

H - 718 entries

I - 867 entries

J - 174 entries

K - 232 entries

L - 950 entries

M - 849 entries

N - 614 entries

O - 430 entries

P - 1431 entries

Q - 309 entries

R - 947 entries

S - 1946 entries

T - 816 entries

U - 362 entries

$\mathcal{U}$ -category (in $\mathcal{U}$ -small) owned by mathcam

$\mathcal{U}$ -small owned by mathcam

ucp convergence (in ucp convergence of processes) owned by gel

ucp convergence of processes owned by gel

ucp topology (in ucp convergence of processes) owned by gel

UFD owned by drini

UFD (in UFD) owned by drini

UFD's are integrally closed owned by rm50

UHP (in upper half plane) owned by brianbirgen

Ulam cloth (=Ulam spiral) owned by PrimeFan

Ulam number owned by PrimeFan

Ulam sequence (in Ulam number) owned by PrimeFan

Ulam spiral owned by PrimeFan

Ulam spiral (=Ulam spiral) owned by PrimeFan

Ulam's Problem (=Collatz problem) owned by akrowne

Ulam-type sequence (in Ulam number) owned by PrimeFan

Ulrich module owned by yshen

ultrabarreled space (=barrel) owned by CWoo

ultrabarrelled (=barrel) owned by CWoo

ultrabarrelled space (in barrel) owned by CWoo

ultra-complex systems owned by bci1

ultraconnected (in ultraconnected space) owned by yark

ultra-connected (in ultraconnected space) owned by yark

ultra-connected space (=ultraconnected space) owned by yark

ultraconnected space owned by yark

ultra filter (=lattice filter) owned by CWoo

ultrafilter (in lattice filter) owned by CWoo

ultrafilter owned by yark

ultra-filter (=lattice filter) owned by CWoo

ultrametric owned by Koro

ultrametric field (in complete ultrametric field) owned by pahio

ultrametric space owned by pahio

ultrametric triangle inequality owned by pahio

ultranet owned by asteroid

ultraparallel (in parallel lines in hyperbolic geometry) owned by Wkbj79

ultraparallel lines (in parallel lines in hyperbolic geometry) owned by Wkbj79

ultraproduct (=reduced direct product) owned by CWoo

ultra-strong-* operator topology (in operator topologies) owned by asteroid

ultra-strong operator topology (in operator topologies) owned by asteroid

ultra-weak operator topology (in operator topologies) owned by asteroid

UMVU (=mean square error) owned by CWoo

UMVUE (=mean square error) owned by CWoo

unambiguity of factorial base representation owned by rspuzio

unary (in arity) owned by Henry

unary relation (in property) owned by drini

unary relation (in relation) owned by CWoo

unbased suspension (in suspension) owned by antonio

unbiased estimator (in bias) owned by CWoo

unbounded (in club) owned by Henry

unbounded (in classes of ordinals and enumerating functions) owned by mathcam

unbounded class (in classes of ordinals and enumerating functions) owned by mathcam

unbounded function (in bounded function) owned by Koro

unbounded linear map (in operator norm) owned by asteroid

unbounded operator (in operator norm) owned by asteroid

unbounded set (in club) owned by Henry

example of unbounded variation (=function of not bounded variation) owned by pahio

uncertainty principle owned by pahio

unconditional convergence owned by kompik

unconditionally convergent (=unconditional convergence) owned by kompik

uncountable owned by yark

uncountable cover (in cover) owned by mps

uncountable set (=uncountable) owned by yark

uncountable sums of positive numbers owned by rspuzio

uncurried function (in currying) owned by mps

undecahedron owned by evin290

under determined owned by akrowne

under-determined (=under determined) owned by akrowne

underdetermined (=under determined) owned by akrowne

example of under-determined polynomial interpolation owned by rmilson

underlying functor (in concrete category) owned by kompik

unicity conjecture for Markov numbers (=uniqueness conjecture for Markov numbers) owned by PrimeFan

uniform absolute continuity (=uniformly integrable) owned by stevecheng

uniform base owned by mathcam

Uniform Boundedness Principle (=Banach-Steinhaus theorem) owned by Koro

uniform continuity owned by CWoo

uniform continuity of Lipschitz functions owned by paolini

uniform continuity over locally compact quantum groupoids owned by bci1

uniform continuity over topological groupoids (in uniform continuity over locally compact quantum groupoids) owned by bci1

uniform continuity over topological groups associated with Hopf algebras (=locally compact quantum groups: uniform continuity) owned by bci1

uniform (continuous) random variable owned by mathcam

uniform convergence owned by Koro

uniform convergence of integral owned by pahio

uniform convergence of series (in sum function of series) owned by pahio

uniform convergence on union interval owned by pahio

uniform dimension owned by mclase

uniform (discrete) random variable owned by Riemann

uniform distribution (=uniform (continuous) random variable) owned by mathcam

uniform expansivity owned by Koro

uniform integrability (=uniformly integrable) owned by stevecheng

uniform-integrability convergence theorem (=Vitali convergence theorem) owned by stevecheng

uniformities on a set form a complete lattice owned by mps

uniformity (in uniform space) owned by mps

uniformity generated by (in fundamental system of entourages) owned by mps

uniformizable (in uniformizable space) owned by CWoo

uniformizable space owned by CWoo

uniformization theorem owned by Simone

proof of the uniformization theorem owned by Simone

uniformizer (in discrete valuation ring) owned by djao

uniformizing element (in discrete valuation ring) owned by djao

uniformly continuous owned by n3o

uniformly continuous (in uniform continuity) owned by CWoo

uniformly continuous function (in uniformly continuous) owned by n3o

uniformly continuous functionals on the Fourier algebra (in locally compact quantum groups: uniform continuity) owned by bci1

uniformly continuous is proximity continuous owned by porton

proof that uniformly continuous is proximity continuous owned by CWoo

uniformly continuous on $\mathbb{R}$ is roughly linear owned by Mathprof

uniformly convergent (in uniform convergence) owned by Koro

uniformly converging integral (in uniform convergence of integral) owned by pahio

uniformly convex (=uniformly convex space) owned by georgiosl

uniformly convex Banach space is reflexive owned by georgiosl

uniformly convex space owned by georgiosl

uniformly distributed owned by bbukh

uniformly equicontinuous owned by Koro

uniformly hyperbolic (=hyperbolic set) owned by Koro

uniformly integrable owned by stevecheng

uniformly locally finite graph owned by sjm1979

uniformly minimum variance unbiased (=mean square error) owned by CWoo

uniform module owned by antizeus

uniform neighborhood owned by CWoo

uniform norm (in bounded function) owned by Koro

uniform proximity (in proximity generated by uniformity) owned by porton

uniform proximity is a proximity owned by CWoo

uniform random variable (=uniform (discrete) random variable) owned by Riemann

uniform random variable (=uniform (continuous) random variable) owned by mathcam

uniform space owned by mps

uniform structure (in uniform space) owned by mps

uniform structure of a metric space owned by n3o

uniform structure of a topological group owned by mps

uniform submodule (in uniform module) owned by antizeus

uniform topology (in topology induced by uniform structure) owned by Mathprof

uniform ultrafilter (in ultrafilter) owned by yark

unimodular owned by whm22

unimodular column (in unimodular matrix) owned by CWoo

unimodular group (in unimodular matrix) owned by CWoo

unimodular group owned by Mathprof

unimodular linear transformation (in unimodular matrix) owned by CWoo

unimodular matrix owned by CWoo

unimodular row (in unimodular matrix) owned by CWoo

unimodular vector (in unimodular matrix) owned by CWoo

union owned by rm50

union (=axiom of union) owned by Sabean

union (in partial ordering on subobjects of an object) owned by CWoo

union bound (in Bonferroni inequalities) owned by kshum

the union of a locally finite collection of closed sets is closed owned by yark

union of non-disjoint connected sets is connected owned by matte

union of subobjects (in partial ordering on subobjects of an object) owned by CWoo

unique colimit of a sequence of cellular inclusions of $CW$

-complexes (in approximation theorem for an arbitrary space) owned by bci1

unique factorization (in UFD) owned by drini

unique factorization and ideals in ring of integers owned by pahio

unique factorization domain (=UFD) owned by drini

uniquely complemented (in uniquely complemented lattice) owned by CWoo

uniquely complemented lattice owned by CWoo

uniquely orthocomplemented (=orthocomplemented lattice) owned by CWoo

uniquely orthocomplemented lattice (in orthocomplemented lattice) owned by CWoo

uniqueness conjecture for Markov numbers owned by PrimeFan

uniqueness of additive identity in a ring owned by alozano

uniqueness of additive inverse in a ring owned by alozano

uniqueness of cardinality owned by mathcam

proof of uniqueness of center of a circle owned by CWoo

uniqueness of division algorithm in Euclidean domain owned by pahio

uniqueness of Fourier expansion owned by pahio

uniqueness of Fourier series (=uniqueness of Fourier expansion) owned by pahio

uniqueness of identity element (=identity element is unique) owned by pahio

uniqueness of inverse (for groups) owned by waj

proof of uniqueness of Lagrange Interpolation formula owned by rspuzio

uniqueness of measures extended from a $\pi$ -system owned by gel

uniqueness of Moebius function owned by mathcam

unit owned by drini

unit (in ring) owned by djao

unit (in unit of adjunction) owned by CWoo

unital (=unit) owned by drini

unital (in ring homomorphism) owned by djao

unital module (=module) owned by yark

unital ring (in ring) owned by djao

unitarily diagonalizable (in diagonalizable operator) owned by asteroid

unitarily equivalent (in Banach *-algebra representation) owned by asteroid

unitary (in McAlister covering theorem) owned by mathcam

unitary owned by asteroid

unitary divisor owned by CompositeFan

unitary element (in involutory ring) owned by CWoo

unitary element (in partial isometry) owned by CWoo

unitary group (in unitary) owned by asteroid

unitary group of a complex Hilbert space (in irreducible unitary representations of compact groups are finite-dimensional) owned by asteroid

unitary matrix (in unitary) owned by asteroid

unitary operator (in unitary) owned by asteroid

unitary perfect number owned by CompositeFan

unitary representation owned by Mathprof

unitary representation of a compact group has a finite-dimensional subrepresentation (=irreducible unitary representations of compact groups are finite-dimensional) owned by asteroid

unitary representation of compact group has an irreducible subrepresentation (in irreducible unitary representations of compact groups are finite-dimensional) owned by asteroid

unitary ring (in ring) owned by djao

unitary space (in unitary) owned by asteroid

unitary transformation (in unitary) owned by asteroid

unit ball (=unit disc) owned by PrimeFan

unit ball (=standard n-ball) owned by Mathprof

unit circle (in unit disk) owned by brianbirgen

unit circle (in circle) owned by PrimeFan

unit coherence (in monoidal category) owned by juanman

unit disc (=unit disk) owned by brianbirgen

unit disc owned by PrimeFan

unit disk owned by brianbirgen

unit disk upper half plane conformal equivalence theorem owned by CWoo

unit divisor (in divisor theory) owned by pahio

unit dyad (in dyad product) owned by pahio

United States (=history of mathematics in the United States of America) owned by PrimeFan

United States of America (=history of mathematics in the United States of America) owned by PrimeFan

United States of America Mathematical Olympiad owned by PrimeFan

unit fraction owned by XJamRastafire

unit fraction series (=Egyptian fraction) owned by milogardner

unit group (=group of units) owned by pahio

unit hyperbola owned by pahio

unit ideal (in fractional ideal of commutative ring) owned by pahio

unities of ring and subring owned by pahio

unitization owned by rspuzio

unit left triangular matrix (=unit triangular matrix) owned by Daume

unit lower triangular matrix (in unit triangular matrix) owned by Daume

unit n-ball (=standard n-ball) owned by Mathprof

unit normal (in Frenet frame) owned by rmilson

unit normal loss function owned by georgiosl

unit object (in monoidal category) owned by juanman

unit of adjunction owned by CWoo

unit right triangular matrix (=unit triangular matrix) owned by Daume

units of quadratic fields owned by pahio

units of real cubic fields with exactly one real embedding owned by Wkbj79

unit space (in topological groupoid) owned by HkBst

unit sphere (in sphere) owned by akrowne

unit tangent (in Frenet frame) owned by rmilson

unit triangular matrix owned by Daume

unit upper triangular matrix (in unit triangular matrix) owned by Daume

unit vector owned by rmilson

derivation of unit vectors in curvilinear coordinates owned by swapnizzle

unity owned by pahio

unity of subring owned by pahio

unity plus nilpotent is unit owned by Wkbj79

univalent (=univalent analytic function) owned by jirka

univalent analytic function owned by jirka

univalent function (=univalent analytic function) owned by jirka

univariate regression model (=regression model) owned by CWoo

universal (=universal relation) owned by Henry

universal (in universal structure) owned by Timmy

universal (=universal mapping property) owned by Algeboy

universal algebra (=algebraic system) owned by CWoo

universal arrow (in universal mapping property) owned by Algeboy

universal assumption owned by Wkbj79

universal bundle owned by mps

universal coefficient theorem owned by mps

universal completion (in universally measurable) owned by gel

universal cover (=universal covering space) owned by bwebste

universal covering space owned by bwebste

universal derivation owned by pbruin

universal enveloping algebra owned by draisma

universal family of spaces (=some examples of universal bundles) owned by bwebste

universal function (in universal relation) owned by Henry

universal hypothesis (=universal assumption) owned by Wkbj79

universality (in universal mapping property) owned by Algeboy

universally complete (in universally measurable) owned by gel

universally measurable owned by gel

universal mapping property owned by Algeboy

universal morphism (in universal mapping property) owned by Algeboy

universal net (=ultranet) owned by asteroid

universal nets in compact spaces are convergent owned by asteroid

universal property (in universal mapping property) owned by Algeboy

universal quantifier (in quantifier) owned by CWoo

universal quantifier operator (in monadic algebra) owned by CWoo

universal relation owned by Henry

universal relations exist for each level of the arithmetical hierarchy owned by Henry

universal structure owned by Timmy

example of a universal structure owned by uzeromay

universal trigonometric substitution (=integration of rational function of sine and cosine) owned by pahio

universal trigonometric substitution (in Weierstrass substitution formulas) owned by Wkbj79

universal Turing machine owned by tromp

universal Turing machines (=artificial intelligence) owned by aplant

universe owned by archibal

universe (=universe of discourse) owned by Jon Awbrey

example of universe owned by rspuzio

universe of discourse owned by Jon Awbrey

example of universe of finite sets owned by rspuzio

unknot owned by basseykay

unordered partition (=integer partition) owned by rm50

unramified (=ramification index) owned by djao

unramified action owned by alozano

unramified extensions and class number divisibility owned by alozano

unramified outside a set of primes (in Hermite's theorem) owned by alozano

unreduced suspension (in suspension) owned by antonio

unrestricted direct product (in direct products of groups) owned by yark

unrestricted direct product of groups (in direct products of groups) owned by yark

unrestricted grammar (=formal grammar) owned by CWoo

unstable (in equilibrium point) owned by Daume

unstable (in transfer function) owned by lha

unstable (in stable marriage problem) owned by mps

unstable cycle (in cycle) owned by Daume

unstable fixed point owned by mathwizard

unstable limit cycle (in limit cycle) owned by Daume

unstable manifold (=stable manifold) owned by Koro

unstable periodic solution (=cycle) owned by Daume

unstable set (=stable manifold) owned by Koro

unstable sorting algorithm (in stable sorting algorithm) owned by mathcam

untouchable number owned by PrimeFan

unusual number owned by PrimeFan

up-arrow (=Knuth's up arrow notation) owned by Henry

up arrow (=Knuth's up arrow notation) owned by Henry

up-arrow notation (=Knuth's up arrow notation) owned by Henry

up arrow notation (=Knuth's up arrow notation) owned by Henry

upper and lower bounds to binomial coefficient owned by rspuzio

proof of upper and lower bounds to binomial coefficient owned by rspuzio

upper asymptotic density (in asymptotic density) owned by mathcam

upper bound owned by djao

upper bound on $\vartheta(n)$ owned by mps

upper central series (in solvable Lie algebra) owned by djao

upper central series (in nilpotent group) owned by djao

upper closed (in upper set) owned by CWoo

upper closure (=upper set) owned by CWoo

upper density (=asymptotic density) owned by mathcam

upper half plane owned by brianbirgen

upper half plane model (=Poincaré upper half plane model) owned by Wkbj79

upper Hessenberg (=Hessenberg matrix) owned by akrowne

upper Hessenberg matrix (=Hessenberg matrix) owned by akrowne

upper limit (in definite integral) owned by mathwizard

upper logarithmic density (in logarithmic density) owned by kompik

upper nilradical owned by CWoo

upper quartile (in percentile) owned by CWoo

upper Riemann sum (in Riemann sum) owned by Wkbj79

upper semiclosed (in ordered space) owned by CWoo

upper semi-continuous (in semicontinuous) owned by bwebste

upper semicontinuous (in semicontinuous) owned by bwebste

upper semilattice (in semilattice) owned by mclase

upper semilattice (in join) owned by yark

upper semimodular lattice (=semimodular lattice) owned by mps

upper set owned by CWoo

upper set operation is a closure operator owned by rspuzio

upper topology (in ordered space) owned by CWoo

upper triangular (in triangular matrix) owned by Wkbj79

upper triangular matrix (in triangular matrix) owned by Wkbj79

up set (=upper set) owned by CWoo

upward directed set (=directed set) owned by yark

upward-directed set (=directed set) owned by yark

upward Lowenheim-Skolem theorem owned by Evandar

ur-element (in terms from foreign languages used in mathematics (html version)) owned by Wkbj79

urelement (in terms from foreign languages used in mathematics (html version)) owned by Wkbj79

Urysohn extension theorem owned by CWoo

Urysohn function (in Urysohn's lemma) owned by yark

Urysohn metrization theorem owned by Evandar

Urysohn's lemma owned by yark

proof of Urysohn's lemma owned by scanez

Urysohn space (=completely Hausdorff) owned by PrimeFan

example of use of Taylor's theorem owned by alozano

example of using Cardano's formulas (=example of solving a cubic equation) owned by pahio

examples using comparison test without limit owned by pahio

using Laplace transform to solve initial value problems owned by pahio

using Minkowski's constant to find a class number owned by alozano

example of a proof using nets owned by yark

using primitive roots and index to solve congruences owned by alozano

example of using residue theorem owned by pahio

example using Stolz-Cesaro theorem owned by georgiosl

using the primitive element of biquadratic field owned by pahio

usual conditions (in filtered probability space) owned by gel

usual hypotheses (in filtered probability space) owned by gel

usual topology (=Euclidean distance) owned by drini

utility owned by Henry

utility (in utility) owned by Henry

utility function (in game) owned by Henry

utility function (in utility) owned by Henry

utilizing limit of $\frac{\sin{x}}{x}$ in 0 (=limit examples) owned by pahio

V - 250 entries

W - 318 entries

X - 8 entries

Y - 22 entries

Z - 97 entries

8278 entries total.
14428 concepts total.

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