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The JNR Property and the Borel Structure of a Banach Space

Oncina, L. (2000)

Serdica Mathematical Journal

Research partially supported by a grant of Caja de Ahorros del Mediterraneo.In this paper we study the property of having a countable cover by sets of small local diameter (SLD for short). We show that in the context of Banach spaces (JNR property) it implies that the Banach space is Cech-analytic. We also prove that to have the JNR property, to be σ- fragmentable and to have the same Borel sets for the weak and the norm topologies, they all are topological invariants of the weak topology. Finally, by...

The Kadec-Pełczyński-Rosenthal subsequence splitting lemma for JBW*-triple preduals

Antonio M. Peralta, Hermann Pfitzner (2015)

Studia Mathematica

Any bounded sequence in an L¹-space admits a subsequence which can be written as the sum of a sequence of pairwise disjoint elements and a sequence which forms a uniformly integrable or equiintegrable (equivalently, a relatively weakly compact) set. This is known as the Kadec-Pełczyński-Rosenthal subsequence splitting lemma and has been generalized to preduals of von Neuman algebras and of JBW*-algebras. In this note we generalize it to JBW*-triple preduals.

The kh-socle of a commutative semisimple Banach algebra

Youness Hadder (2020)

Mathematica Bohemica

Let 𝒜 be a commutative complex semisimple Banach algebra. Denote by kh ( soc ( 𝒜 ) ) the kernel of the hull of the socle of 𝒜 . In this work we give some new characterizations of this ideal in terms of minimal idempotents in 𝒜 . This allows us to show that a “result” from Riesz theory in commutative Banach algebras is not true.

The K-theory of the triple-Toeplitz deformation of the complex projective plane

Jan Rudnik (2012)

Banach Center Publications

π j i : B i B i j = B j i , i,j ∈ 1,2,3, i ≠ j, of C*-epimorphisms assuming that it satisfies the cocycle condition. Then we show how to compute the K-groups of the multi-pullback C*-algebra of such a family, and exemplify it in the case of the triple-Toeplitz deformation of ℂP².

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