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
John Edensor Littlewood
surface form: J. E. Littlewood
introducedIn 20th century
namedAfter G. H. Hardy
John Edensor Littlewood
surface form: 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 Singular Integrals and Differentiability Properties of Functions
surface form: 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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Referenced by (4)

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

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