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Artículo
Invariant subspaces and Deddens algebras
(Elsevier, 2015)
It is shown that if the Deddens algebra DT associated with a quasinilpotent operator T on a complex Banach space is closed and localizing then T has a nontrivial closed hyperinvariant subspace.
Artículo
Fixed points, selections and common fixed points for nonexpansive-type mappings
(Elsevier, 2011-10-15)
We study the existence of fixed points in the context of uniformly convex geodesic metric spaces, hyperconvex spaces and Banach spaces for single and multivalued mappings satisfying conditions that generalize the concept ...
Artículo
Fixed points of single- and set-valued mappings in uniformly convex metric spaces with no metric convexity
(SpringerOpen, 2010)
We study the existence of fixed points and convergence of iterates for asymptotic pointwise contractions in uniformly convex metric spaces. We also study the existence of fixed points for setvalued nonexpansive mappings ...
Artículo
The Szlenk index and the fixed point property under renorming
(Springer Open, 2010)
Assume that X is a Banach space such that its Szlenk index Sz X is less than or equal to the first infinite ordinal ω. We prove that X can be renormed in such a way that X with the resultant norm satisfies R X < 2, where ...
Artículo
Exponential decay estimates for singular integral operators
(Springer, 2013-12)
The following subexponential estimate for commutators is proved |{x ∈ Q : |[b, T]f(x)| > tM2 f(x)}| ≤ c e− √ α tkbkBMO |Q|, t > 0. where c and α are absolute constants, T is a Calder´on–Zygmund operator, M is the Hardy ...
Artículo
Large algebras of singular functions vanishing on prescribed sets
(Springer, 2016-06-21)
In this paper, the non-vacuousness of the family of all nowhere analytic infinitely differentiable functions on the real line vanishing on a prescribed set Z is characterized in terms of Z. In this case, large algebraic ...
Artículo
Does Kirk’s theorem hold for multivalued nonexpansive mappings?
(Springer Open, 2010)
Fixed Point Theory for multivalued mappings has many useful applications in Applied Sciences, in particular, in Game Theory and Mathematical Economics. Thus, it is natural to try of extending the known fixed point results ...
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 ...
Artículo
À la carte recurrence relations for continuous and discrete hypergeometric functions
(Sociedad Española de Matemática Aplicada, 2011-09)
We show how, using the constructive approach for special functions introduced by Nikiforov and Uvarov, one can obtain recurrence relations for the hypergeometric-type functions not only for the continuous case but also ...
Artículo
Heisenberg uniqueness pairs and the Klein-Gordon equation
(Princeton University, 2011)
A Heisenberg uniqueness pair (HUP) is a pair (Γ, Λ), where Γ is a curve in the plane and Λ is a set in the plane, with the following property: any bounded Borel measure µ in the plane supported on Γ, which is absolutely ...