Now showing items 1-7 of 7

    • Conditional quasi-greedy bases in non-superreflexive Banach spaces 

      Albiac Alesanco, Fernando José Upna Orcid; Ansorena, José L.; Wojtaszczyk, Przemyslaw (Springer, 2019)   Artículo / Artikulua  OpenAccess
      For a conditional quasi-greedy basis B in a Banach space, the associated conditionality constants km[B] verify the estimate km[B]=O(logm). Answering a question raised by Temlyakov, Yang, and Ye, several authors have studied ...
    • Existence of almost greedy bases in mixed-norm sequence and matrix spaces, including besov spaces 

      Albiac Alesanco, Fernando José Upna Orcid; Ansorena, José L.; Bello, Glenier; Wojtaszczyk, Przemyslaw (Springer, 2023)   Artículo / Artikulua  OpenAccess
      We prove that the sequence spaces lp ⊕ lq and the spaces of infinite matrices lp(lq ), lq l(p) and ( ∞ n=1 n lp)lq , which are isomorphic to certain Besov spaces, have an almost greedy basis whenever 0 < p < 1 < q < ∞. ...
    • Greedy approximation for biorthogonal systems in quasi-Banach spaces 

      Albiac Alesanco, Fernando José Upna Orcid; Ansorena, José L.; Berná, Pablo M.; Wojtaszczyk, Przemyslaw (Instytut Matematyczny, 2021)   Artículo / Artikulua  OpenAccess
      The general problem addressed in this work is the development of a systematic study of the thresholding greedy algorithm for general biorthogonal systems in quasi-Banach spaces from a functional-analytic point of view. If ...
    • On a 'philosophical' question about Banach envelopes 

      Albiac Alesanco, Fernando José Upna Orcid; Ansorena, José L.; Wojtaszczyk, Przemyslaw (Springer, 2021)   Artículo / Artikulua  OpenAccess
      We show how to construct non-locally convex quasi-Banach spaces X whose dual separates the points of a dense subspace of X but does not separate the points of X. Our examples connect with a question raised by Pietsch (Rev ...
    • On certain subspaces of p for 0 < p ≤ 1 and their applications to conditional quasi-greedy bases in p-Banach spaces 

      Albiac Alesanco, Fernando José Upna Orcid; Ansorena, José L.; Wojtaszczyk, Przemyslaw (Springer, 2021)   Artículo / Artikulua  OpenAccess
      We construct for each 0<p≤1 an infinite collection of subspaces of ℓp that extend the example of Lindenstrauss (Bull. Acad. Polon. Sci. Sér. Sci. Math. Astronom. Phys. 12, 539–542, 1964) of a subspace of ℓ1 with no ...
    • Quasi-greedy bases in ℓp (0 < p < 1) are democratic 

      Albiac Alesanco, Fernando José Upna Orcid; Ansorena, José L.; Wojtaszczyk, Przemyslaw (Elsevier, 2020)   Artículo / Artikulua  OpenAccess
      The list of known Banach spaces whose linear geometry determines the (nonlinear) democracy functions of their quasi-greedy bases to the extent that they end up being democratic, reduces to c0, ℓ2, and all separable L1-spaces. ...
    • Uniqueness of unconditional basis of Hp(T) ⊕ 2 and Hp(T) ⊕ T (2) for 0 < p < 1 

      Albiac Alesanco, Fernando José Upna Orcid; Ansorena, José L.; Wojtaszczyk, Przemyslaw (Elsevier, 2022)   Artículo / Artikulua  OpenAccess
      Our goal in this paper is to advance the state of the art of the topic of uniqueness of unconditional basis. To that end we establish general conditions on a pair (X, Y) formed by a quasi-Banach space X and a Banach ...

      El Repositorio ha recibido la ayuda de la Fundación Española para la Ciencia y la Tecnología para la realización de actividades en el ámbito del fomento de la investigación científica de excelencia, en la Línea 2. Repositorios institucionales (convocatoria 2020-2021).
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