Hasil untuk "math.FA"

Ahmed Ghatasheh

This article demonstrates that the recent proof of the invariant subspace problem, as presented by Khalil et al., is incorrect.

Tim Dalby

Another proof that uniformly nonsquare Banach spaces have the fixed point property is presented.

Dirk Werner

This note surveys Wolfgang Lusky's proof of uniqueness of the Gurariy spaces and mentions further developments.

Anna Pelczar-Barwacz

We construct a reflexive Banach space $X$ with a subspace isometric to $X$, which is not complemented in $X$.

Rajendra Bhatia, Rajesh Sharma

We obtain some inequalities which are stronger than the Schur majorization inequalities.

Gérard Bourdaud

We establish the most general Szasz type estimates for homogeneous Besov and Lizorkin-Triebel spaces, and their realizations.

Éric Ricard

We give variations on Ando's result comparing $f(B)-f(A)$ and $f(|B-A|)$ with respect to unitarily invariant norms on matrices.

Tijani Pakhrou

It is shown that for any W weakly compact set of a real Banach space X, the set $L_\infty(μ,W)$ is N-simultaneously proximinal in $L_\infty(μ,X)$ for arbitrary monotonous norm N in $\mathbb{R}^n$.

Pekka Koskela, ZhengZhu

We show that the extension results by Mazya and Poborchi for polynomial planar cusps can be realized via composition operators generated by reflections.

Piotr Mikusiński

Maps between spaces of measures on measurable spaces $(X,Σ_X)$ and $(Y, Σ_Y)$ are treated as generalized functions between $X$ and $Y$.

H. Garth Dales

We show that each maximal ideal in a commutative Banach algebra has codimension 1.

Anna Novikova

Generalization of Lyapunov convexity theorem is proved for vector measure with values in Banach spaces with unconditional bases, which are q-concave for some $q<\infty.$

Adam Paszkiewicz

In any infinite dimensional Hilbert space H, a sequence P_n...P_1 x diverges in norm for some x \in H and orthogonal projections P_n \in {Q_1,..., Q_5}.

Adam Paszkiewicz

In any infinite dimensional Hilbert space $\mathcal H$ there exist orthogonal projections $Q_1$, $Q_2$ and $Q_3$, such that a sequence $(P_n... P_1(x))$ diverges in norm for some $P_1,P_2,...\in\{Q_1,Q_2,Q_3\}$ and $x\in\mathcal H$.

Lucio S. Fassarella

A characterization of positive operators on finite dimensional complex vector spaces based on the Routh-Hurwitz Criterion.

Eleftherios Nikolidakis

We prove a sharp integral inequality which connects the dyadic maximal operator with the Hardy operator. We also give some applications of this inequality.

Peng Gao

We extend a result of Levin and Stečkin concerning an inequality analogous to Hardy's inequality.

Joerg Eschmeier

This paper has been withdrawn by the author. There is an error on page 3 in the last inequality before Lemma 1.1.

Hadi Haghshenas

The aim of this paper is state of conditions that ensure the convexity of a Chebyshev sets in Hilbert spaces .

Michel Talagrand

We construct an exhaustive submeasure that is not equivalent to a measure. This solves problems of J. von Neumann (1937) and D. Maharam (1947).