Hardy–Littlewood maximal function

E120395

The Hardy–Littlewood maximal function is a fundamental operator in real analysis and harmonic analysis that controls the local averages of a function and plays a key role in differentiation theorems and singular integral theory.

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Predicate Object
instanceOf mathematical operator
maximal operator
object in harmonic analysis
object in real analysis
actsOn locally integrable functions
codomain measurable functions
context Euclidean harmonic analysis
controls local averages of a function
definitionType supremum of local averages
domain functions on Euclidean space
functions on ℝⁿ
field harmonic analysis
real analysis
generalizationOf one-dimensional Hardy–Littlewood maximal operator
generalizationTo metric measure spaces
spaces of homogeneous type
introducedBy G. H. Hardy
J. E. Littlewood
introducedIn 20th century
namedAfter G. H. Hardy
J. E. Littlewood
playsKeyRoleIn real-variable methods in harmonic analysis
property bounded on Lᵖ for 1 < p ≤ ∞
not bounded on L¹ in strong sense
sublinear
translation invariant (centered version)
weak-type (1,1)
relatedTo Calderón–Zygmund theory
Lebesgue differentiation theorem
Muckenhoupt Aₚ weights
Vitali covering lemma
singular integral operators
satisfies maximal inequality
strong (p,p) inequality for 1 < p ≤ ∞
weak (1,1) maximal inequality
typicalMeasure Lebesgue measure
usedFor Lebesgue differentiation theorem
boundedness of singular integrals
differentiation theorems
interpolation arguments
singular integral theory
weak-type estimates
usedToProve almost everywhere convergence of averages
boundedness of Calderón–Zygmund operators
variant centered maximal function
dyadic maximal function
fractional maximal function
uncentered maximal function

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

G. H. Hardy knownFor Hardy–Littlewood maximal function
G. H. Hardy notableFor Hardy–Littlewood maximal function
subject linked to: Godfrey
John Edensor Littlewood knownFor Hardy–Littlewood maximal function
Singular Integrals and Differentiability Properties of Functions topic Hardy–Littlewood maximal operator
linked to: Hardy–Littlewood maximal function