Buscar
Mostrando ítems 1-10 de 22
Artículo
Diversities, hyperconvexity and fixed points
(Elsevier, 2014-01)
Diversities have been recently introduced as a generalization of metrics for which a rich tight span theory could be stated. In this work we take up a number of questions about hyperconvexity, diversities and fixed points ...
Artículo
The τ-fixed point property for left reversible semigroups
(Springer Open, 2015-12)
In this article we use the generalized Gossez-Lami Dozo property and the Opial condition to study the fixed point property for left reversible semigroups in separable Banach spaces. As a consequence, some previous results ...
Artículo
Spectral methods for bivariate Markov processes with diffusion and discrete components and a variant of the Wright-Fisher model
(Elsevier, 2012-09-01)
The aim of this paper is to study differential and spectral properties of the infinitesimal operator of two dimensional Markov processes with diffusion and discrete components. The infinitesimal operator is now a second-order ...
Artículo
The L(log L)e endpoint estimate for maximal singular integral operators
(Elsevier, 2015-08-01)
We prove in this paper the following estimate for the maximal operator T ∗ associated to the singular integral operator T: kT ∗ fkL 1,∞ (w) . 1 ǫ Z Rn | f(x)| ML(log L) ǫ (w)(x) dx, w ≥ 0, 0 < ǫ ≤ 1. This ...
Artículo
Optimal exponents in weighted estimates without examples
(International Press, 2015)
t. We present a general approach for proving the optimality of the exponents on weighted estimates. We show that if an operator T satisfies a bound like kT kLp(w) ≤ c [w] β Ap w ∈ Ap, then the optimal lower bound ...
Artículo
Some new properties of composition operators associated with lens maps
(Springer, 2013-05)
We give examples of results on composition operators connected with lens maps. The first two concern the approximation numbers of those operators acting on the usual Hardy space H2. The last ones are connected with ...
Artículo
Hardy-Littlewood inequalities for norms of positive operators on sequence spaces
(Elsevier, 2013-01-01)
We consider estimates of Hardy and Littlewood for norms of operators on sequence spaces, and we apply a factorization result of Maurey to obtain improved estimates and simplified proofs for the special case of a positive operator.
Artículo
Compact composition operators on the Dirichlet space and capacity of sets of contact points
(Elsevier, 2013-02-15)
We prove several results about composition operators on the Dirichlet space D⁎. For every compact set K⊆∂D of logarithmic capacity , there exists a Schur function φ both in the disk algebra A(D) and in D⁎ such that the ...
Artículo
On the Muskat problem: global in time results in 2D and 3D
(Johns Hopkins University Press, 2016-12)
This paper considers the three dimensional Muskat problem in the stable regime. We obtain a conservation law which provides an L2 maximum principle for the fluid interface. We also show global in time existence for strong ...
Artículo
A proof of a trigonometric inequality. A glimpse inside the mathematical kitchen
(2011-09)
We prove the inequality ∞ ∑ k=1(−1) k+1 rk cos kφ k+2 < ∞ ∑ k=1 (−1) k+1 rk k+2 for 0 < r 1 and 0 < φ < π . For the case r = 1 we give two proofs. The first one is by means of a general numerical technique (Maximal Slope ...