This is an announcement for the paper "Characterization of
quasi-Banach spaces which coarsely embed into a Hilbert space" by
N. L. Randrianarivony.
Abstract: A map f between two metric spaces (X,d_1) and (Y,d_2) is called
a coarse embedding of X into Y if there exist two nondecreasing functions
phi_1, phi_2:[0,\infty) --> [0,\infty) such that:
phi_1(d_1(x,y)) \leq d_2(f(x),f(y)) \leq phi_2(d_1(x,y)) for all x, y in
X, and phi_1(t) tends to \infty as t tends to \infty. We characterize
those quasi-Banach spaces that have a coarse embedding into a
Hilbert space.
Archive classification: Functional Analysis; Metric Geometry
Remarks: 3 pages
The source file(s), LovaGenAMM.4.tex: 6257 bytes, is(are) stored in
gzipped form as 0411269.gz with size 3kb. The corresponding postcript
file has gzipped size 25kb.
Submitted from: nirina(a)math.tamu.edu
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This is an announcement for the paper "Hyperbolic groups admit proper
affine isometric actions on $l^p$-spaces" by Guoliang Yu.
Abstract: In this paper, we show that hyperbolic groups admit proper
affine isometric actions on $l^p$-spaces.
Archive classification: Group Theory; Operator Algebras
Remarks: 10 pages (to appear in GAFA)
The source file(s), hyplp.tex: 17579 bytes, is(are) stored in gzipped
form as 0411234.gz with size 6kb. The corresponding postcript file has
gzipped size 37kb.
Submitted from: gyu(a)math.vanderbilt.edu
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/math.GR/0411234
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http://arXiv.org/abs/math.GR/0411234
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This is an announcement for the paper "Fragmentability and representations
of flows" by Michael Megrelishvili.
Abstract: Our aim is to study weak star continuous representations of
semigroup actions into the duals of ``good'' (e.g., reflexive and Asplund)
Banach spaces. This approach leads to flow analogs of Eberlein and
Radon-Nikodym compacta and a new class of functions (Asplund functions)
which intimately is connected with Asplund representations and includes
the class of weakly almost periodic functions.
We show that a flow is weakly almost periodic iff it admits sufficiently
many
reflexive representations.
One of the main technical tools in this paper is the concept of
fragmentability (which actually comes from Namioka and Phelps) and
widespreadly used in topological aspects of Banach space theory.
We explore fragmentability as ``a generalized equicontinuity'' of
flows. This
unified approach allows us to obtain several dynamical applications. We
generalize and strengthen some results of Akin-Auslander-Berg,
Shtern, Veech-Troallic-Auslander and Hansel-Troallic. We establish that
frequently, for linear G-actions, weak and strong topologies coincide on,
not necessarily closed, G-minimal subsets. For instance such actions are
``orbitwise Kadec``.
Archive classification: Functional Analysis; General Topology
Mathematics Subject Classification: 54H15; 43A60
Citation: Topology Proceedings, 27:2, 2003, 497-544
Remarks: 30 pages
The source file(s), RN.tex: 154972 bytes, diagrams.tex: 116119 bytes,
is(are) stored in gzipped form as 0411112.tar.gz with size 82kb. The
corresponding postcript file has gzipped size 129kb.
Submitted from: megereli(a)math.biu.ac.il
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This is an announcement for the paper "A sharp isoperimetric bound for
convex bodies" by Ravi Montenegro.
Abstract: We consider the problem of lower bounding a generalized
Minkowski measure of subsets of a convex body with a log-concave
probability measure, conditioned on the set size. A bound is given
in terms of diameter and set size, which is sharp for all set sizes,
dimensions, and norms. In the case of uniform density a stronger theorem
is shown which is also sharp.
Archive classification: Functional Analysis; Metric Geometry; Probability
Mathematics Subject Classification: 52A40
The source file(s), iso.bbl: 1295 bytes, iso.tex: 41335 bytes, is(are)
stored in gzipped form as 0411018.tar.gz with size 14kb. The corresponding
postcript file has gzipped size 52kb.
Submitted from: monteneg(a)yahoo.com
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/math.FA/0411018
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http://arXiv.org/abs/math.FA/0411018
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This is an announcement for the paper "A class of Banach spaces with
few non strictly singular operators" by S. A. Argyros, J. Lopez-Abad
and S. Todorcevic.
Abstract: We construct a family $(\mathcal{X}_\al)_{\al\le \omega_1}$
of reflexive Banach spaces with long transfinite bases but with no
unconditional basic sequences. In our spaces $\mathcal{X}_\al$ every
bounded operator $T$ is split into its diagonal part $D_T$ and its
strictly singular part $S_T$.
Archive classification: Functional Analysis; Logic
Mathematics Subject Classification: 46B20; 03E05
Remarks: 52 pages, 1 figure
The source file(s), om1hi.tex: 254359 bytes, om1hi1.eps: 181035 bytes,
is(are) stored in gzipped form as 0312522.tar.gz with size 117kb. The
corresponding postcript file has gzipped size 333kb.
Submitted from: jlopez(a)crm.es
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/math.FA/0312522
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http://arXiv.org/abs/math.FA/0312522
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CHAIR IN PURE MATHEMATICS AT LANCASTER UNIVERSITY
Broad field: Pure Mathematics
Duration: Indefinite
Position: Professor
Institution: Department of Mathematics and Statistics, Lancaster University
Starting date: 1.4.05 (or preferably before 1.9.05)
Area(s) preferred: Analysis
Contact person(s): Professor S.C. Power, s.power(a)lancaster.ac.uk
Application deadline: 7.1.05
Other comments: Job reference number A374
Full details: Personnel Services, Lancaster University
Telephone: (01524) 846549
WWW: http://www.personnel.lancs.ac.uk/vacancydets.aspx?jobid=A374
This is an announcement for the paper "The Busemann-Petty problem in
hyperbolic and spherical spaces" by V.Yaskin.
Abstract: The Busemann-Petty problem asks whether origin-symmetric
convex bodies in $\mathbb{R}^n$ with smaller central hyperplane sections
necessarily have smaller $n$-dimensional volume. It is known that the
answer to this problem is affirmative if $n\le 4$ and negative if $n\ge
5$. We study this problem in hyperbolic and spherical spaces.
Archive classification: Functional Analysis
Mathematics Subject Classification: 52Axx
Remarks: 16 pages, 2 figures
The source file(s), HyperbolicBP.tex: 38485 bytes, pic02.eps: 9386
bytes, picForVlad2.eps: 3824 bytes, is(are) stored in gzipped form as
0410501.tar.gz with size 15kb. The corresponding postcript file has
gzipped size 68kb.
Submitted from: yaskinv(a)math.missouri.edu
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/math.FA/0410501
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This is an announcement for the paper "Modified Busemann-Petty problem
on sections of convex bodies" by A.Koldobsky, V.Yaskin and M.Yaskina.
Abstract: The Busemann-Petty problem asks whether origin-symmetric
convex bodies in $\mathbb{R}^n$ with smaller central hyperplane sections
necessarily have smaller $n$-dimensional volume. It is known that the
answer is affirmative if $n\le 4$ and negative if $n\ge 5$. In this
article we modify the assumptions of the original Busemann-Petty problem
to guarantee the affirmative answer in all dimensions.
Archive classification: Functional Analysis
Mathematics Subject Classification: 52Axx
Remarks: 17 pages
The source file(s), modBP.tex: 33931 bytes, is(are) stored in gzipped
form as 0410496.gz with size 10kb. The corresponding postcript file has
gzipped size 64kb.
Submitted from: yaskinv(a)math.missouri.edu
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/math.FA/0410496
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http://arXiv.org/abs/math.FA/0410496
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This is an announcement for the paper "$\ell_p$ (p>2) does not coarsely
embed into a Hilbert space" by W. B. Johnson and N. L. Randrianarivony.
Abstract: A coarse embedding of a metric space X into a metric space Y
is a map f: X-->Y satisfying for every x, y in X:
\phi_1(d(x,y)) \leq d(f(x),f(y)) \leq \phi_2(d(x,y)) where \phi_1 and
\phi_2 are nondecreasing functions on [0,\infty) with values
in [0,\infty), with the condition that \phi_1(t) tends to \infty as t
tends to \infty.
We show that \ell_p does not coarsely embed in a Hilbert space for
2<p<\infty.
Archive classification: Functional Analysis
Remarks: 10 pages
The source file(s), coarselpl2.9.tex: 14916 bytes, is(are) stored in
gzipped form as 0410427.gz with size 5kb. The corresponding postcript
file has gzipped size 36kb.
Submitted from: nirina(a)math.tamu.edu
The paper may be downloaded from the archive by web browser from URL
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This is an announcement for the paper "Markov chains in smooth Banach
spaces and Gromov hyperbolic metric spaces" by Assaf Naor, Yuval Peres,
Oded Schramm and Scott Sheffield.
Abstract: A metric space $X$ has {\em Markov type\/} $2$, if for
any reversible finite-state Markov chain $\{Z_t\}$ (with $Z_0$ chosen
according to the stationary distribution) and any map $f$ from the state
space to $X$, the distance $D_t$ from $f(Z_0)$ to $f(Z_t)$ satisfies
$\E(D_t^2) \le K^2\, t\, \E(D_1^2)$ for some $K=K(X)<\infty$. This
notion is due to K.\,Ball (1992), who showed its importance for the
Lipschitz extension problem. However until now, only Hilbert space (and
its bi-Lipschitz equivalents) were known to have Markov type 2. We show
that every Banach space with modulus of smoothness of power type $2$ (in
particular, $L_p$ for $p>2$) has Markov type $2$; this proves a conjecture
of Ball. We also show that trees, hyperbolic groups and simply connected
Riemannian manifolds of pinched negative curvature have Markov type
$2$. Our results are applied to settle several conjectures on Lipschitz
extensions and embeddings. In particular, we answer a question posed by
Johnson and Lindenstrauss in 1982, by showing that for $1<q<2<p<\infty$,
any Lipschitz mapping from a subset of $L_p$ to $L_q$ has a Lipschitz
extension defined on all of $L_p$.
Archive classification: Functional Analysis; Probability
Mathematics Subject Classification: 46B99 (primary), 60B99 (secondary)
Remarks: 27 pages
The source file(s), Mtype.tex: 95789 bytes, lang.fig: 18215 bytes,
lang.pstex: 17247 bytes, lang.pstex_t: 859 bytes, is(are) stored
in gzipped form as 0410422.tar.gz with size 38kb. The corresponding
postcript file has gzipped size 129kb.
Submitted from: anaor(a)microsoft.com
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