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On the weak (1,1) boundedness of a class of oscillatory singular integrals

Yibiao Pan (1993)

Studia Mathematica

We prove the uniform weak (1,1) boundedness of a class of oscillatory singular integrals under certain conditions on the phase functions. Our conditions allow the phase function to be completely flat. Examples of such phase functions include ϕ ( x ) = e - 1 / x 2 and ϕ ( x ) = x e - 1 / | x | . Some related counterexample is also discussed.

On weak minima of certain integral functionals

Gioconda Moscariello (1998)

Annales Polonici Mathematici

We prove a regularity result for weak minima of integral functionals of the form Ω F ( x , D u ) d x where F(x,ξ) is a Carathéodory function which grows as | ξ | p with some p > 1.

On weak type inequalities for rare maximal functions

K. Hare, A. Stokolos (2000)

Colloquium Mathematicae

The properties of rare maximal functions (i.e. Hardy-Littlewood maximal functions associated with sparse families of intervals) are investigated. A simple criterion allows one to decide if a given rare maximal function satisfies a converse weak type inequality. The summability properties of rare maximal functions are also considered.

On weak type inequalities for rare maximal functions in ℝⁿ

A. M. Stokolos (2006)

Colloquium Mathematicae

The study of one-dimensional rare maximal functions was started in [4,5]. The main result in [5] was obtained with the help of some general procedure. The goal of the present article is to adapt the procedure (we call it "dyadic crystallization") to the multidimensional setting and to demonstrate that rare maximal functions have properties not better than the Strong Maximal Function.

On weakly A-harmonic tensors

Bianca Stroffolini (1995)

Studia Mathematica

We study very weak solutions of an A-harmonic equation to show that they are in fact the usual solutions.

On weighted inequalities for operators of potential type

Shiying Zhao (1996)

Colloquium Mathematicae

In this paper, we discuss a class of weighted inequalities for operators of potential type on homogeneous spaces. We give sufficient conditions for the weak and strong type weighted inequalities sup_{λ>0} λ|{x ∈ X : |T(fdσ)(x)|>λ }|_{ω}^{1/q} ≤ C (∫_{X} |f|^{p}dσ)^{1/p} and (∫_{X} |T(fdσ)|^{q}dω )^{1/q} ≤ C (∫_X |f|^{p}dσ )^{1/p} in the cases of 0 < q < p ≤ ∞ and 1 ≤ q < p < ∞, respectively, where T is an operator of potential type, and ω and σ are Borel measures on the homogeneous...

Ondelettes et poids de Muckenhoupt

Pierre Lemarié-Rieusset (1994)

Studia Mathematica

We study, for a basis of Hölderian compactly supported wavelets, the boundedness and convergence of the associated projectors P j on the space L p ( d μ ) for some p in ]1,∞[ and some nonnegative Borel measure μ on ℝ. We show that the convergence properties are related to the A p criterion of Muckenhoupt.

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