This is an announcement for the paper "On the closed subideals of
$L(\ell_p\oplus\ell_q)$" by Thomas Schlumprecht.
Abstract: In this paper we first review the known results about the closed
subideals of the space of bounded operator on $\ell_p\oplus \ell_q$,
$1<p<q<\infty$, and then construct several new ones.
Archive classification: math.FA
Mathematics Subject Classification: Primary: 47L20. Secondary: 47B10,
47B37
Remarks: To appear in Operators and Matrices
Submitted from: schlump(a)math.tamu.edu
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/1105.3610
or
http://arXiv.org/abs/1105.3610
This is an announcement for the paper "Descriptive properties of elements
of biduals of Banach spaces" by Pavel Ludvik and Jiri Spurny.
Abstract: If $E$ is a Banach space, any element $x^{**}$ in its bidual
$E^{**}$ is an affine function on the dual unit ball $B_{E^*}$ that
might possess variety of descriptive properties with respect to the weak*
topology. We prove several results showing that descriptive properties of
$x^{**}$ are quite often determined by the behaviour of $x^{**}$ on the
set of extreme points of $B_{E^*}$, generalizing thus results of J. Saint
Raymond and F. Jellett. We also prove several results on relation between
Baire classes and intrinsic Baire classes of $L_1$-preduals which were
introduced by S.A. Argyros, G. Godefroy and H.P. Rosenthal. Also, several
examples witnessing natural limits of our positive results are presented.
Archive classification: math.FA
Mathematics Subject Classification: 46B99, 46A55, 26A21
Submitted from: spurny(a)karlin.mff.cuni.cz
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/1105.3413
or
http://arXiv.org/abs/1105.3413
This is an announcement for the paper "Coarse embedding into uniformly
convex Banach space" by Qinggang Ren.
Abstract: In this paper, we study the coarse embedding into Banach
space. We proved that under certain conditions, the property of embedding
into Banach space can be preserved under taking the union the metric
spaces. For a group $G$ strongly relative hyperbolic to a subgroup $H$,
we proved that if $H$ admits a coarse embedding into a uniformly convex
Banach space, so is $B(n)=\{g\in G|\abs{g}_{S\cup\mathscr{H}}\leq n\}$.
Archive classification: math.MG math.FA
Remarks: 14 pages
Submitted from: qinggang.ren(a)hw4.ecs.kyoto-u.ac.jp
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/1105.3263
or
http://arXiv.org/abs/1105.3263
This is an announcement for the paper "Grothendieck-Lidskii theorem
for subspaces and factor spaces of L_p-spaces" by Oleg Reinov and
Qaisar Latif.
Abstract: In 1955, A. Grothendieck has shown that if the linear operator
$T$ in a Banach subspace of an $L_\infty$-space is $2/3$-nuclear
then the trace of $T$ is well defined and is equal to the sum of all
eigenvalues $\{\mu_k(T)\}$ of $T.$ V.B. Lidski\v{\i} , in 1959, proved his
famous theorem on the coincidence of the trace of the $S_1$-operator in
$L_2(\nu)$ with its spectral trace $\sum_{k=1}^\infty \mu_k(T).$ We show
that for $p\in[1,\infty]$ and $s\in (0,1]$ with $1/s=1+|1/2-1/p|,$ and for
every $s$-nuclear operator $T$ in every subspace of any $L_p(\nu)$-space
the trace of $T$ is well defined and equals the sum of all eigenvalues
of $T.$
Archive classification: math.FA
Mathematics Subject Classification: 47B06
Remarks: LaTeX2e, 5 pages
Submitted from: orein51(a)mail.ru
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/1105.2914
or
http://arXiv.org/abs/1105.2914
This is an announcement for the paper "Relative entropies for convex
bodies" by Justin Jenkinson and Elisabeth Werner.
Abstract: We introduce a new class of (not necessarily convex) bodies
and show, among other things, that these bodies provide yet another
link between convex geometric analysis and information theory. Namely,
they give geometric interpretations of the relative entropy of the cone
measures of a convex body and its polar and related quantities.
Such interpretations were first given by Paouris and Werner for
symmetric convex bodies in the context of the $L_p$-centroid
bodies. There, the relative entropies appear after performing second
order expansions of certain expressions. Now, no symmetry assumptions are
needed. Moreover, using the new bodies, already first order expansions
make the relative entropies appear. Thus, these bodies detect ``faster"
details of the boundary of a convex body than the $L_p$-centroid bodies.
Archive classification: math.FA
Submitted from: elisabeth.werner(a)case.edu
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/1105.2846
or
http://arXiv.org/abs/1105.2846
This is an announcement for the paper "Spaceability for the weak form of
Peano's theorem and vector-valued sequence spaces" by Cleon Barroso,
Geraldo Botelho, Vinicius V. Favaro and Daniel Pellegrino.
Abstract: Two new applications of a technique for spaceability are
given in this paper. For the first time this technique is used in the
investigation of the algebraic genericity property of the weak form of
Peano's theorem on the existence of solutions of the ODE $u'=f(u)$ on
$c_0$. The space of all continuous vector fields $f$ on $c_0$ is proved
to contain a closed $\bf c$-dimensional subspace formed by fields $f$ for
which -- except for the null field -- the weak form of Peano's theorem
fails to be true. The second application generalizes known results on
the existence of closed $\bf c$-dimensional subspaces inside certain
subsets of $\ell_p(X)$-spaces, $0 < p < \infty$, to the existence of
closed subspaces of maximal dimension inside such subsets.
Archive classification: math.FA
Remarks: 10 pages
Submitted from: dmpellegrino(a)gmail.com
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/1105.2845
or
http://arXiv.org/abs/1105.2845
This is an announcement for the paper "Finite order spreading models"
by S.A. Argyros, V. Kanellopoulos and K. Tyros.
Abstract: Extending the classical notion of the spreading model,
the $k$-spreading models of a Banach space are introduced, for every
$k\in\mathbb{N}$. The definition, which is based on the $k$-sequences and
plegma families, reveals a new class of spreading sequences associated
to a Banach space. Most of the results of the classical theory are
stated and proved in the higher order setting. Moreover, new phenomena
like the universality of the class of the 2-spreading models of $c_0$
and the composition property are established. As consequence, a problem
concerning the structure of the $k$-iterated spreading models is solved.
Archive classification: math.FA
Remarks: 41 pages, no figures
Submitted from: chcost(a)gmail.com
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/1105.2732
or
http://arXiv.org/abs/1105.2732
This is an announcement for the paper "Examples of k-iterated spreading
models" by Spiros A. Argyros and Pavlos Motakis.
Abstract: It is shown that for every $k\in\mathbb{N}$ and every spreading
sequence $\{e_n\}_{n\in\mathbb{N}}$ that generates a uniformly convex
Banach space $E$, there exists a uniformly convex Banach space $X_{k+1}$
admitting $\{e_n\}_{n\in\mathbb{N}}$ as a $k+1$-iterated spreading model,
but not as a $k$-iterated one.
Archive classification: math.FA
Remarks: 16 pages, no figures
Submitted from: pmotakis(a)central.ntua.gr
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/1105.2714
or
http://arXiv.org/abs/1105.2714
This is an announcement for the paper "Isomorphic properties of
intersection bodies" by A. Koldobsky, G. Paouris and M. Zymonopoulou.
Abstract: We study isomorphic properties of two generalizations of
intersection bodies, the class of k-intersection bodies and the class
of generalized k-intersection bodies. We also show that the Banach-Mazur
distance of the k-intersection body of a convex body, when it exists and
it is convex, with the Euclidean ball, is bounded by a constant depending
only on k, generalizing a well-known result of Hensley and Borell. We
conclude by giving some volumetric estimates for k-intersection bodies.
Archive classification: math.FA
Submitted from: marisa.zym(a)gmail.com
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/1105.2629
or
http://arXiv.org/abs/1105.2629
This is an announcement for the paper "Bounded and unbounded
polynomials and multilinear forms: Characterizing continuity" by Jose
L. Gamez-Merino, Gustavo A. Munoz-Fernandez, Daniel Pellegrino and Juan
B. Seoane-Sepulveda.
Abstract: In this paper we prove a characterization of continuity for
polynomials on a normed space. Namely, we prove that a polynomial is
continuous if and only if it maps compact sets into compact sets. We also
provide a partial answer to the question as to whether a polynomial is
continuous if and only if it transforms connected sets into connected
sets. These results motivate the natural question as to how many
non-continuous polynomials there are on an infinite dimensional normed
space. A problem on the \emph{lineability} of the sets of non-continuous
polynomials and multilinear mappings on infinite dimensional normed
spaces is answered.
Archive classification: math.FA
Remarks: 8 pages
Submitted from: dmpellegrino(a)gmail.com
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/1105.1737
or
http://arXiv.org/abs/1105.1737