Lebesgue measure

E284674

Lebesgue measure is the standard way of assigning a consistent notion of "length," "area," or "volume" to subsets of Euclidean space, forming the foundation of modern measure theory and integration.

All labels observed (3)

How this entity was disambiguated

Statements (52)

Predicate Object
instanceOf Borel measure
complete measure
measure
outer measure
translation-invariant measure
agreesWith Riemann integral on Riemann integrable functions
allowsIntegrationOf functions not Riemann integrable
assignsMeasure R^n has infinite measure
countable subset of R^n has measure 0
empty set has measure 0
finite set in R^n has measure 0
interval [a,b] has measure b-a
singleton set in R^n has measure 0
constructedBy Carathéodory’s extension theorem
surface form: Carathéodory extension theorem
constructedFrom outer measure via coverings by intervals or rectangles
definedOn Lebesgue measurable subsets of R^n
sigma-algebra of Lebesgue measurable sets
dependsOn axiom of choice for existence of non-measurable sets
extends Jordan measure
notion of area on rectangles
notion of length on intervals
notion of volume on boxes in R^n
generalizes area in R^2
length in R
volume in R^3
hasNonMeasurableSets Vitali set
hasNullSet Cantor set
introducedIn early 20th century
isAbsolutelyContinuousWithRespectTo itself
isComplete true
isCountablyAdditive true
isFoundationOf Lebesgue integration
modern measure theory
isInnerRegularOnOpenSets true
isInvariantUnder orthogonal transformations in R^n
translations in R^n
isOuterRegularOnBorelSets true
isRegular true
isRotationInvariant true
isSigmaFinite true
isTranslationInvariant true
isUniqueUpToScaling among translation-invariant sigma-finite measures on R^n
isZeroOn sets of Hausdorff dimension less than n in R^n (under suitable conditions)
namedAfter Henri Lebesgue
satisfies continuity from above for decreasing sequences of sets with finite measure
continuity from below
monotonicity property
takesValuesIn [0,+∞]
usedFor Fourier analysis on R^n
defining L^p spaces
ergodic theory on Euclidean spaces
probability theory on R^n

How these facts were elicited

Referenced by (11)

Full triples — surface form annotated when it differs from this entity's canonical label.

Lebesgue integration usesConcept Lebesgue measure
Lebesgue spaces basedOn Lebesgue measure
Henri Lebesgue knownFor Lebesgue measure
Henri Lebesgue notableConcept Lebesgue measure
this entity surface form: Lebesgue outer measure
Tonelli's theorem holdsFor Lebesgue measure
this entity surface form: Lebesgue measure on Euclidean spaces
Kolmogorov axioms compatibleWith Lebesgue measure
Bernstein set relatedConcept Lebesgue measure
Steinhaus theorem involvesConcept Lebesgue measure
measure theory usesConcept Lebesgue measure
measure theory notableMeasure Lebesgue measure