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Mostrando ítems 11-20 de 38
Artículo
Approximation and entropy numbers of composition operators
(De Gruyter, 2020-10-17)
We give a survey on approximation numbers of composition operators on the Hardy space, on thedisk and on the polydisk, and add corresponding new results on their entropy numbers, revealing how theyare different.
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
Some revisited results about composition operators on Hardy spaces
(European Mathematical Society, 2012)
We generalize, on one hand, some results known for composition operators on Hardy spaces to the case of Hardy-Orlicz spaces HΨ: construction of a “slow” Blaschke product giving a non-compact composition operator on ...
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
Approximation numbers of composition operators on the Hardy space of the infinite polydisk
(Springer, 2017-12)
We study the composition operators of the Hardy space on D∞ ∩ℓ1, the ℓ1 part of the infinite polydisk, and the behavior of their approximation numbers.
Artículo
Infinitesimal Carleson property for weighted measures induced by analytic self-maps of the unit disk
(Springer, 2013-08)
We prove that, for every α>−1, the pull-back measure φ(Aα) of the measure dAα(z)=(α+1)(1−|z|2)αdA(z), where A is the normalized area measure on the unit disk D, by every analytic self-map φ:D→D is not only an (α+2)-Carleson ...
Artículo
Approximation numbers of composition operators on Hp
(De Gruyter Open, 2015-01)
We give estimates for the approximation numbers of composition operators on the Hp spaces, 1 ≤ p < ∞.
Artículo
Function algebras with a strongly precompact unit ball
(Elsevier, 2013-10-01)
Let µ be a finite positive Borel measure with compact support K ⊆ C, and regard L∞(µ) as an algebra of multiplication operators on the Hilbert space L2(µ). Then consider the subalgebra A(K) of all continuous functions on ...
Artículo
Two results on composition operators on the Dirichlet space
(Elsevier, 2015-06-15)
We show that the decay of approximation numbers of compact composition operators on the Dirichlet space D can be as slow as we wish. We also prove the optimality of a result of O. El-Fallah, K. Kellay, M. Shabankhah ...
Artículo
Approximation numbers of composition operators on the Dirichlet space
(Springer, 2015-04)
We study the decay of approximation numbers of compact composition operators on the Dirichlet space. We give upper and lower bounds for these numbers. In particular, we improve on a result of O. El-Fallah, K. Kellay, M. ...