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A class of Banach sequence spaces analogous to the space of Popov

Parviz Azimi, A. A. Ledari (2009)

Czechoslovak Mathematical Journal

Hagler and the first named author introduced a class of hereditarily l 1 Banach spaces which do not possess the Schur property. Then the first author extended these spaces to a class of hereditarily l p Banach spaces for 1 p < . Here we use these spaces to introduce a new class of hereditarily l p ( c 0 ) Banach spaces analogous of the space of Popov. In particular, for p = 1 the spaces are further examples of hereditarily l 1 Banach spaces failing the Schur property.

A coding of separable Banach spaces. Analytic and coanalytic families of Banach spaces

Benoit Bossard (2002)

Fundamenta Mathematicae

When the set of closed subspaces of C(Δ), where Δ is the Cantor set, is equipped with the standard Effros-Borel structure, the graph of the basic relations between Banach spaces (isomorphism, being isomorphic to a subspace, quotient, direct sum,...) is analytic non-Borel. Many natural families of Banach spaces (such as reflexive spaces, spaces not containing ℓ₁(ω),...) are coanalytic non-Borel. Some natural ranks (rank of embedding, Szlenk indices) are shown to be coanalytic ranks. Applications...

A common fixed point theorem for a commuting family of weak* continuous nonexpansive mappings

Sławomir Borzdyński, Andrzej Wiśnicki (2014)

Studia Mathematica

It is shown that if 𝓢 is a commuting family of weak* continuous nonexpansive mappings acting on a weak* compact convex subset C of the dual Banach space E, then the set of common fixed points of 𝓢 is a nonempty nonexpansive retract of C. This partially solves an open problem in metric fixed point theory in the case of commutative semigroups.

A comparative analysis of Bernstein type estimates for the derivative of multivariate polynomials

Szilárd Gy. Révész (2006)

Annales Polonici Mathematici

We compare the yields of two methods to obtain Bernstein type pointwise estimates for the derivative of a multivariate polynomial in a domain where the polynomial is assumed to have sup norm at most 1. One method, due to Sarantopoulos, relies on inscribing ellipses in a convex domain K. The other, pluripotential-theoretic approach, mainly due to Baran, works for even more general sets, and uses the pluricomplex Green function (the Zaharjuta-Siciak extremal function). When the inscribed ellipse method...

A dichotomy on Schreier sets

Robert Judd (1999)

Studia Mathematica

We show that the Schreier sets S α ( α < ω 1 ) have the following dichotomy property. For every hereditary collection ℱ of finite subsets of ℱ, either there exists infinite M = ( m i ) i = 1 such that S α ( M ) = m i : i E : E S α , or there exist infinite M = ( m i ) i = 1 , N such that [ N ] ( M ) = m i : i F : F a n d F N S α .

A generalized projection decomposition in Orlicz-Bochner spaces

Henryk Hudzik, Ryszard Płuciennik, Yuwen Wang (2005)

Banach Center Publications

In this paper, a precise projection decomposition in reflexive, smooth and strictly convex Orlicz-Bochner spaces is given by the representation of the duality mapping. As an application, a representation of the metric projection operator on a closed hyperplane is presented.

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