Person: Cobos Díaz, Fernando
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First Name
Fernando
Last Name
Cobos Díaz
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Matemáticas
Department
Análisis Matemático Matemática Aplicada
Area
Análisis Matemático
Identifiers
4 results
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Item Approximation and entropy numbers of embeddings between approximation spaces(Constructive Approximation, 2018) Cobos Díaz, Fernando; Domínguez Bonilla, Óscar; Kühn, ThomasItem On nuclearity of embeddings between Besov spaces(Journal of Approximation Theory, 2018) Cobos Díaz, Fernando; Domínguez Bonilla, Óscar; Kühn, ThomasLet Bp,qs,α(Ω) be the Besov space with classical smoothness s and additional logarithmic smoothness of order α on a bounded Lipschitz domain Ω in Rd. For s1, s2 ∈ R, 1 ≤ p1, p2, q1, q2 ≤ ∞ and s1 − s2 = d − d(1/p2 − 1/p1)+, we show a sufficient condition on q1, q2 for nuclearity of embedding Bs1,α1 (superíndices) y p1, q1 (subíndices)(Ω) → Bp2,α2 (superíndice) y s2 q,2 (subíndices) (Ω). We also show that the condition is necessary in a wide range of parameters.Item Compact operators and approximation spaces(Colloquium mathematicum, 2014) Cobos Díaz, Fernando; Domínguez Bonilla, Óscar; Martínez, AntónWe investigate compact operators between approximation spaces, paying special attention to the limit case. Applications are given to embeddings between Besov spaces.Item Characterizations of logarithmic Besov spaces in terms of differences, Fourier-analytical decompositions, wavelets and semi-groups.(Journal of Functional Analysis, 2016) Cobos Díaz, Fernando; Domínguez Bonilla, Óscar; Triebel, HansWe work with Besov spaces Bp,q0,b defined by means of differences, with zero classical smoothness and logarithmic smoothness with exponent b. We characterize Bp,q0,b by means of Fourier-analytical decompositions, wavelets and semi-groups. We also compare those results with the well-known characterizations for classical Besov spaces Bp,qs.