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Artículo
Improving dimension estimates for Furstenberg-type sets
(Elsevier, 2010-01-30)
In this paper we study the problem of estimating the generalized Hausdorff dimension of Furstenberg sets in the plane. For α∈(0,1], a set F in the plane is said to be an α-Furstenberg set if for each direction e there is ...
Artículo
Borderline weighted estimates for commutators of singular integrals
(Springer, 2016)
In this paper we establish the following estimate w({x∈Rn:|[b,T]f(x)|>λ})≤cTε2∫RnΦ(∥b∥BMO|f(x)|λ)ML(logL)1+εw(x)dx where w≥0,0<ε<1 and Φ(t)=t(t+log+(t)). This inequality relies upon the following sharp Lp estimate ∥[b ...
Artículo
Artículo
Extended eigenvalues for Cesàro operators
(Elsevier, 2015-09-15)
A complex scalar λ is said to be an extended eigenvalue of a bounded linear operator T on a complex Banach space if there is a nonzero operator X such that T X = λXT. Such an operator X is called an extended eigenoperator ...
Artículo
The multilinear strong maximal function
(Springer, 2011-01)
A multivariable version of the strong maximal function is introduced and a sharp distributional estimate for this operator in the spirit of the Jessen, Marcinkiewicz, and Zygmund theorem is obtained. Conditions that ...
Artículo
Generalized asymptotic pointwise contractions and nonexpansive mappings involving orbits
(Springer Open, 2010)
We give fixed point results for classes of mappings that generalize pointwise contractions, asymptotic contractions, asymptotic pointwise contractions, and nonexpansive and asymptotic nonexpansive mappings. We consider the ...
Artículo
Algebraic genericity of strict-order integrability
(Polish Academy of Sciences, Institute of Mathematics, 2010)
We provide sharp conditions on a measure µ defined on a measurable space X guaranteeing that the family of functions in the Lebesgue space Lp (µ, X) (p ≥ 1) which are not integrable with order q for any q > p (or any q < ...
Artículo
Borsuk-Dugundji type extension theorems with Busemann convex target spaces
(Finnish Academy of Science and Letters, 2018)
In this work we study continuity properties of convex combinations in Busemann convex geodesic spaces and apply them to obtain two extension results for continuous and Lipschitz mappings with values in a Busemann convex space.
Artículo
Wardowski conditions to the coincidence problem
(Frontiers Media, 2015-08-31)
In this article we first discuss the existence and uniqueness of a solution for the coincidence problem: Find p ∈ X such that Tp = Sp, where X is a nonempty set, Y is a complete metric space, and T, S:X → Y are two mappings ...