Información del autor
Autor Cobos, Fernando |
Documentos disponibles escritos por este autor (121)
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Besoy, Blanca F. ; Cobos, Fernando | 2019We derive interpolation formulae for the measure of non-compactness of operators interpolated by logarithmic methods with ? = 0, 1 between quasi-Banach spaces. Applications are given to operators between Lorentz-Zygmund spaces.texto impreso
Besoy, Blanca F. ; Cobos, Fernando | 2020We derive interpolation formulae for the measure of non-compactness of operators interpolated by logarithmic methods with [?] = 0; 1 between quasi-Banach spaces. Applications are given to operators between Lorentz-Zygmund spaces.texto impreso
This volume details some of the latest advances in spectral theory and nonlinear analysis through various cutting-edge theories on algebraic multiplicities, global bifurcation theory, non-linear Schrödinger equations, non-linear boundary value p[...]texto impreso
Cobos, Fernando ; Fernández-Cabrera, Luz M. ; Manzano, Antonio ; Martínez, Antón | Heldermann Verlag | 2007Let A0 and A1 be quasi-Banach spaces with A0 ,! A1. By means of a direct approach, we show that the interpolation spaces on (A0;A1) generated by the function parameter tµ(1 + j log tj)¡b can be expressed in terms of classical real inter-polation[...]texto impreso
We investigate pointwise domination property in operator spaces generated by Lorentz sequence spacestexto impreso
We give a maximal description in the sense of Aronszajn-Gagliardo for the real method in the category of quasi-Banach spaces.texto impreso
We establish an estimate for the measure of non-compactness of an interpolated operator acting from a J-space into a K-space. Our result refers to general Banach N-tuples. We also derive estimates for entropy numbers if some of the N-tuples redu[...]texto impreso
We establish formulae for the measure of non-compactness of operators interpolated by limiting methods that come up by the choice ?=0 and ?=1 in the definition of the real method.texto impreso
The authors consider multiparameter scales of interpolation spaces and prove a general form of the Wolff reiteration theorem [cf. T. H. Wolff, Lecture Notes Math. 908, 199- 204 (1982)] for n- tuples of Banach spaces. The proof, based on the use [...]texto impreso
We give some new examples of bounded multilinear forms on th Hilbert spaces 2 and L2(0,?). We characterize those which are compact or Hilbert-Schmidt. In particular, we study m-linear forms (m ? 3) on 2 which can be regarded as the multilinear[...]texto impreso
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We study interpolation methods associated to polygons and establish estimates for the norms of interpolated operators. Our results explain the geometrical base of estimates in the literature. Applications to interpolation of weighted L(p)-spaces[...]texto impreso
Let d ? N and let ? be a bounded Lipschitz domain in Rd. We prove that the embedding Id : Bd (?) ?? L (log L) (?) is nuclear if atexto impreso
Cobos, Fernando ; Fernandez-Cabrera, Luz ; Kuehn, Thomas ; Ullrich, Tino | Academic Press-Elsevier Science | 2009We investigate the limit class of interpolation spaces that comes up by the choice ? = 0 in the definition of the real method. These spaces arise naturally interpolating by the J -method associated to the unit square. Their duals coincide with t[...]texto impreso
Working on the d-torus, we show that Besov spaces Bps(Lp(logL)a) modelled on Zygmund spaces can be described in terms of classical Besov spaces. Several other properties of spaces Bps(Lp(logL)a) are also established. In particular, in the critic[...]texto impreso
We compare Besov spaces B-p,q(0,b) with zero classical smoothness and logarithmic smoothness b defined by using the Fourier transform with the corresponding spaces:B-p,q(0,b) defined by means of the modulus of smoothness. In particular, we show [...]texto impreso
Let ? = (A? , A?) , B? = (B? , B?) be Banach couples, let E be a Banach space and let T be a bilinear operator such that ||T(a, b)||? ? M[sub]j ||a||?[sub]j ||b||?[sub]j for a ? A? ? A?, b ? B? ? B?, j = 0, 1. If T : A°[sub]j × B°[sub]j ?? E com[...]texto impreso
Let H denote a Hilbert space, T a compact operator on H, {sn(T)}1 n=1 the eigenvalues of |T|, and Sp (p > 0) the set of all such T for which {sn(T)}1 n=1 is in `p. If A and B are bounded linear operators on L2, say that B pointwise dominates A [...]texto impreso
Cobos, Fernando ; Fernández-Martínez, Pedro ; Martínez, Antón ; Raynaud, Yves | Cambridge Univ Press | 1999We study the relationship between the dual of the #C-space defined by means of a polygon and the /-space generated by the dual N-tuple. The results complete the research started in [4]. Special attention is paid to the case when the N-tuple is f[...]texto impreso
In a previous paper, the authors laid the foundations of a theory of Schatten±von Neumann classes 'p (0!p%¢) of trilinear forms in Hilbert space. This paper continues that research. In the n-dimensional case, it is shown that the best constant d[...]texto impreso
We show a direct proof for the generalized Hardy’s inequality obtained by the first author Math. Nachr. 126, 281-300, 1986. Our techniques are elementary and work in the limit case which was not covered in [loc. cit.]. Some applications to eigen[...]texto impreso
We determine the smallest Schatten class containing all integral operators with kernels in L(p)(L(p',q))symm, where 2texto impreso
We study the interpolation properties of Asplund operators by the complex method, as well as by general J - and K-methods.texto impreso
Cobos, Fernando ; Fernández-Cabrera, Luz M. ; Martínez, Antón | Gauthier-Villars/Editions Elsevier | 2006We show a necessary and sufficient condition on the lattice ? for the general real method (· , ·)? to preserve the Banach-algebra structure. As an application we derive factorization of weakly compact homomorphisms through interpolation properti[...]texto impreso
The authors investigate the behaviour of bilinear operators under interpolation by the methods associated to polygons. These methods, working with N-tuples (N _ 3) of Banach spaces instead of couples, were introduced by F. Cobos and J. Peetre [P[...]