A new proof of weighted weak-type inequalities for fractional integrals
We give a new and simpler proof of a two-weight, weak inequality for fractional integrals first proved by Cruz-Uribe and Pérez [4].
The minimal operator and the geometric maximal operator in ℝⁿ
We prove two-weight norm inequalities in ℝⁿ for the minimal operator , extending to higher dimensions results obtained by Cruz-Uribe, Neugebauer and Olesen [8] on the real line. As an application we extend to ℝⁿ weighted norm inequalities for the geometric maximal operator , proved by Yin and Muckenhoupt [27]. We also give norm inequalities for the centered minimal operator, study powers of doubling weights and give sufficient conditions for the geometric maximal operator to be equal to the closely...
On the two-weight problem for singular integral operators
We give type conditions which are sufficient for two-weight, strong inequalities for Calderón-Zygmund operators, commutators, and the Littlewood-Paley square function . Our results extend earlier work on weak inequalities in [13].
Weighted norm inequalities for the geometric maximal operator.
Weighted endpoint estimates for commutators of fractional integrals
Given , , and , we give sufficient conditions on weights for the commutator of the fractional integral operator, , to satisfy weighted endpoint inequalities on and on bounded domains. These results extend our earlier work [3], where we considered unweighted inequalities on .
The one-sided minimal operator and the one-sided reverse Holder inequality
We introduce the one-sided minimal operator, , which is analogous to the one-sided maximal operator. We determine the weight classes which govern its two-weight, strong and weak-type norm inequalities, and show that these two classes are the same. Then in the one-weight case we use this class to introduce a new one-sided reverse Hölder inequality which has several applications to one-sided weights.
Norm inequalities for the minimal and maximal operator, and differentiation of the integral.
We study the weighted norm inequalities for the minimal operator, a new operator analogous to the Hardy-Littlewood maximal operator which arose in the study of reverse Hölder inequalities. We characterize the classes of weights which govern the strong and weak-type norm inequalities for the minimal operator in the two weight case, and show that these classes are the same. We also show that a generalization of the minimal operator can be used to obtain information about the differentiability of the...
Extensions of Rubio de Francia's extrapolation theorem.
One of the main results in modern harmonic analysis is the extrapolation theorem of J. L. Rubio de Francia for A weights. In this paper we discuss some recent extensions of this result. We present a new approach that, among other things, allows us to obtain estimates in rearrangement-invariant Banach function spaces as well as weighted modular inequalities. We also extend this extrapolation technique to the context of A weights. We apply the obtained results to the dyadic square function. Fractional...
On the continuity of minimizers for quasilinear functionals
In this paper we establish a continuity result for local minimizers of some quasilinear functionals that satisfy degenerate elliptic bounds. The non-negative function which measures the degree of degeneracy is assumed to be exponentially integrable. The minimizers are shown to have a modulus of continuity controlled by . Our proof adapts ideas developed for solutions of degenerate elliptic equations by J. Onninen, X. Zhong: Continuity of solutions of linear, degenerate elliptic equations, Ann....
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