Iterations of Hardy-Littlewood maximal functions

On the Variation of the Hardy–littlewood Maximal Function

We show that a function f : R → R of bounded variation satisfies VarMf ≤ C Var f, where Mf is the centered Hardy–Littlewood maximal function of f . Consequently, the operator f 7→ (Mf) is bounded from W (R) to L(R). This answers a question of Hajłasz and Onninen in the one-dimensional case.

Regularity of the Hardy-littlewood Maximal Operator on Block Decreasing Functions

We study the Hardy-Littlewood maximal operator defined via an unconditional norm, acting on block decreasing functions. We show that the uncentered maximal operator maps block decreasing functions of special bounded variation to functions with integrable distributional derivatives, thus improving their regularity. In the special case of the maximal operator defined by the l∞-norm, that is, by a...

A Sharp Estimate for the Hardy-littlewood Maximal Function

The best constant in the usual L norm inequality for the centered Hardy-Littlewood maximal function on R is obtained for the class of all “peak-shaped” functions. A function on the line is called “peakshaped” if it is positive and convex except at one point. The techniques we use include variational methods. AMS Classification (1991): 42B25 0. Introduction. Let (0.1) (Mf)(x) = sup δ>0 1 2δ ∫ x+δ

Vector A2 Weights and a Hardy-littlewood Maximal Function

An analogue of the Hardy-Littlewood maximal function is introduced, for functions taking values in finite-dimensional Hilbert spaces. It is shown to be L bounded with respect to weights in the class A2 of Treil, thereby extending a theorem of Muckenhoupt from the scalar to the vector case. A basic chapter of the subject of singular integral operators is the weighted norm theory, which provides ...

On the Hardy - Littlewood majorant