Pełnotekstowe zasoby PLDML oraz innych baz dziedzinowych są już dostępne w nowej Bibliotece Nauki.
Zapraszamy na https://bibliotekanauki.pl
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 3

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available remote

A conditional quasi-greedy basis of l₁

100%
Dilworth S., Mitra D.
Studia Mathematica
|
2001
|
tom 144
|
nr 1
95-100
EN
We show that the Lindenstrauss basic sequence in l₁ may be used to construct a conditional quasi-greedy basis of l₁, thus answering a question of Wojtaszczyk. We further show that the sequence of coefficient functionals for this basis is not quasi-greedy.
2
Content available remote

Quasi-greedy bases and Lebesgue-type inequalities

81%
Dilworth S., Soto-Bajo M., Temlyakov V.
Studia Mathematica
|
2012
|
tom 211
|
nr 1
41-69
EN
We study Lebesgue-type inequalities for greedy approximation with respect to quasi-greedy bases. We mostly concentrate on the $L_{p}$ spaces. The novelty of the paper is in obtaining better Lebesgue-type inequalities under extra assumptions on a quasi-greedy basis than known Lebesgue-type inequalities for quasi-greedy bases. We consider uniformly bounded quasi-greedy bases of $L_{p}$, 1 < p < ∞, and prove that for such bases an extra multiplier in the Lebesgue-type inequality can be taken as C(p)ln(m+1). The known magnitude of the corresponding multiplier for general (no assumption of uniform boundedness) quasi-greedy bases is of order $m^{|1/2-1/p|}$, p ≠ 2. For uniformly bounded orthonormal quasi-greedy bases we get further improvements replacing ln(m+1) by $(ln(m+1))^{1/2}$.
3
Content available remote

On the existence of almost greedy bases in Banach spaces

81%
Dilworth S., Kalton N., Kutzarova D.
Studia Mathematica
|
2003
|
tom 159
|
nr 1
67-101
EN
We consider several greedy conditions for bases in Banach spaces that arise naturally in the study of the Thresholding Greedy Algorithm (TGA). In particular, we continue the study of almost greedy bases begun in [3]. We show that almost greedy bases are essentially optimal for n-term approximation when the TGA is modified to include a Chebyshev approximation. We prove that if a Banach space X has a basis and contains a complemented subspace with a symmetric basis and finite cotype then X has an almost greedy basis. We show that c₀ is the only $ℒ_{∞}$ space to have a quasi-greedy basis. The Banach spaces which contain almost greedy basic sequences are characterized.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.