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Uniqueness of unconditional bases in c 0 -products

P. Casazza, N. Kalton (1999)

Studia Mathematica

We give counterexamples to a conjecture of Bourgain, Casazza, Lindenstrauss and Tzafriri that if X has a unique unconditional basis (up to permutation) then so does c 0 ( X ) . We also give some positive results including a simpler proof that c 0 ( 1 ) has a unique unconditional basis and a proof that c 0 ( p n N n ) has a unique unconditional basis when p n 1 , N n + 1 2 N n and ( p n - p n + 1 ) l o g N n remains bounded.

Uniqueness of unconditional bases of c 0 ( l p ) , 0 < p < 1

C. Leránoz (1992)

Studia Mathematica

We prove that if 0 < p < 1 then a normalized unconditional basis of a complemented subspace of c 0 ( l p ) must be equivalent to a permutation of a subset of the canonical unit vector basis of c 0 ( l p ) . In particular, c 0 ( l p ) has unique unconditional basis up to permutation. Bourgain, Casazza, Lindenstrauss, and Tzafriri have previously proved the same result for c 0 ( l ) .

w * -basic sequences and reflexivity of Banach spaces

Kamil John (2005)

Czechoslovak Mathematical Journal

We observe that a separable Banach space X is reflexive iff each of its quotients with Schauder basis is reflexive. Similarly if ( X , Y ) is not reflexive for reflexive X and Y then ( X 1 , Y ) is is not reflexive for some X 1 X , X 1 having a basis.

Wavelet bases in L p ( )

Gustaf Gripenberg (1993)

Studia Mathematica

It is shown that an orthonormal wavelet basis for L 2 ( ) associated with a multiresolution is an unconditional basis for L p ( ) , 1 < p < ∞, provided the father wavelet is bounded and decays sufficiently rapidly at infinity.

Weakly Compact Generating and Shrinking Markusevic Bases

Fabian, M., Hájek, P., Montesinos, V., Zizler, V. (2006)

Serdica Mathematical Journal

2000 Mathematics Subject Classification: 46B30, 46B03.It is shown that most of the well known classes of nonseparable Banach spaces related to the weakly compact generating can be characterized by elementary properties of the closure of the coefficient space of Markusevic bases for such spaces. In some cases, such property is then shared by all Markusevic bases in the space.

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