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We prove that if X is an infinite-dimensional Banach space with C^p smooth partitions of unity, then X and X\K are C^p diffeomorphic, for every weakly compact subset K of X.

Functional Analysis · Mathematics 2007-05-23 Daniel Azagra , Alejandro Montesinos

In this note the following is proved. Separable L-embedded spaces - that is separable Banach spaces which are complemented in their biduals such that the norm between the two complementary subspaces is additive - have property (X) which, by…

Functional Analysis · Mathematics 2007-05-23 Hermann Pfitzner

We show that a representation of a Banach algebra $A$ on a Banach space $X$ can be extended to a canonical representation of $A^{**}$ on $X$ if and only if certain orbit maps $A\to X$ are weakly compact. When this is the case, we show that…

Functional Analysis · Mathematics 2018-03-26 Eusebio Gardella , Hannes Thiel

We show that every unital amenable separable simple $C^*$-algebra with finite tracial rank which satisfies the UCT has in fact tracial rank at most one. We also show that unital separable simple $C^*$-algebrass which are "tracially" locally…

Operator Algebras · Mathematics 2012-05-29 Huaxin Lin

We consider the properties weak cancellation, K_1-surjectivity, good index theory, and K_1-injectivity for the class of extremally rich C*-algebras, and for the smaller class of isometrically rich C*-algebras. We establish all four…

Operator Algebras · Mathematics 2017-06-09 Lawrence G. Brown , Gert K. Pedersen

We generalized the Korkin-Zolotarev theorem to the case of entire functions having the smallest $L^1$ norm on a system of intervals $E$. If $\bbC\setminus E$ is a domain of Widom type with the Direct Cauchy Theorem we give an explicit…

Classical Analysis and ODEs · Mathematics 2012-04-23 Peter Yuditskii

We consider a Banach algebra $A$ with the property that, roughly speaking, sufficiently many irreducible representations of $A$ on nontrivial Banach spaces do not vanish on all square zero elements. The class of Banach algebras with this…

Operator Algebras · Mathematics 2013-07-09 J. Alaminos , M. Brešar , J. Extremera , Š. Špenko , A. R. Villena

In this paper we consider the unbounded local completely positive and local completely contractive maps on maximal tensor product of unital locally C*-algebras and discuss on extremal points of certain convex subsets in the set of such…

Operator Algebras · Mathematics 2023-12-27 Maria Joita

For A a separable unital C*-algebra and M a separable McDuff II_1-factor, we show that the space Hom_w(A,M) of weak approximate unitary equivalence classes of unital *-homomorphisms A \rightarrow M may be considered as a closed, bounded,…

Operator Algebras · Mathematics 2015-12-02 Scott Atkinson

Recent developments in Banach space theory provided unexpected examples of unital Banach algebras that are isomorphic to Calkin algebras of Banach spaces, however no example of a unital Banach algebra that cannot be realised as a~Calkin…

Functional Analysis · Mathematics 2021-12-13 Bence Horváth , Tomasz Kania

Let $K$ be a commutative compact hypergroup and $L^1(K)$ the hypergroup algebra. We show that $L^1(K)$ is amenable if and only if $\pi_K$, the Plancherel weight on the dual space $\widehat{K}$, is bounded. Furthermore, we show that if $K$…

Functional Analysis · Mathematics 2009-09-09 Ahmadreza Azimifard

We investigate the extremal properties of the unit ball of $L(X)_w^*$, the dual space of bounded linear operators defined on a Banach space $X$ equipped with the numerical radius norm. As an application of the present study, we obtain a…

Functional Analysis · Mathematics 2026-04-07 Subhadip Pal , Saikat Roy , Debmalya Sain

It is proved that in a commutative unital Banach algebra, every non-maximal closed prime ideal is accessible. Specifically, it can be represented as the intersection of all closed ideals of the algebra that properly contain it.…

Functional Analysis · Mathematics 2025-05-09 Ramesh Garimella

We show that finite dimensional Banach spaces fail to be uniformly non locally almost square. Moreover, we construct an equivalent almost square bidual norm on $\ell_\infty.$ As a consequence we get that every dual Banach space containing…

Functional Analysis · Mathematics 2020-03-10 Trond A. Abrahamsen , Petr Hájek , Stanimir Troyanski

We construct infinitely differentiable norms and partitions of unity for a class of Banach spaces which includes all spaces $\C(K)$ with $K$ a countable compact space, and all spaces $\C_0[0,\Omega )$ with $\Omega $ an ordinal.

Functional Analysis · Mathematics 2008-02-03 Richard Haydon

We prove the existence of extremal, non-csc, K\"ahler metrics on certain unstable projectivised vector bundles $\P (E) \to M$ over a cscK-manifold $M$ with discrete holomorphic automorphism group, in certain adiabatic K\"ahler classes. In…

Differential Geometry · Mathematics 2015-11-03 Till Brönnle

In this paper we associate to every reduced C*-algebraic quantum group A a universal C*-algebraic quantum group. We fine tune a proof of Kirchberg to show that every *-representation of a modified L1-space is generated by a unitary…

Operator Algebras · Mathematics 2007-05-23 Johan Kustermans

We construct uncountably many mutually nonisomorphic simple separable stably finite unital exact C$^\ast$-algebras which are not isomorphic to their opposite algebras. In particular, we prove that there are uncountably many possibilities…

Operator Algebras · Mathematics 2024-02-14 N. Christopher Phillips , Maria Grazia Viola

For any metric space X, the predual of Lip(X) is unique. If X has finite diameter or is complete and convex --- in particular, if it is a Banach space --- then the predual of Lip_0(X) is unique.

Functional Analysis · Mathematics 2016-11-10 Nik Weaver

We present a Lebesgue-type decomposition for a representable functional on a $^*$-algebra into absolutely continuous and singular parts with respect to an other. This generalizes the corresponding results of S. P. Gudder for unital Banach…

Functional Analysis · Mathematics 2014-06-25 Zsigmond Tarcsay