This is an announcement for the paper "Hilbert space structure and
positive operators" by D. Drivaliaris and N. Yannakakis.
Abstract: Let X be a real Banach space. We prove that the existence of an
injective, positive, symmetric and not strictly singular operator from X
into its dual implies that either X admits an equivalent Hilbertian norm
or it contains a nontrivially complemented subspace which is isomorphic
to a Hilbert space. We also treat the non-symmetric case.
Archive classification: math.FA
Mathematics Subject Classification: 46B03; 46C15; 47B99
Citation: Journal of Mathematical Analysis and Applications 305 (2)
(2005),
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This is an announcement for the paper "Subspaces with a common complement
in a Banach space" by D. Drivaliaris and N. Yannakakis.
Abstract: We study the problem of the existence of a common algebraic
complement for a pair of closed subspaces of a Banach space. We prove
the following two characterizations: (1) The pairs of subspaces of a
Banach space with a common complement coincide with those pairs which
are isomorphic to a pair of graphs of bounded linear operators between
two other Banach spaces. (2) The pairs of subspaces of a Banach space
X with a common complement coincide with those pairs for which there
exists an involution S on X exchanging the two subspaces, such that
I+S is bounded from below on their union. Moreover we show that, in
a separable Hilbert space, the only pairs of subspaces with a common
complement are those which are either equivalently positioned or not
completely asymptotic to one another. We also obtain characterizations
for the existence of a common complement for subspaces with closed sum.
Archive classification: math.FA
Mathematics Subject Classification: 46B20; 46C05; 47A05
Citation: Studia Mathematica 182 (2) (2007), 141-164
The source file(s), common_arxiv.tex: 74237 bytes, is(are) stored in
gzipped form as 0805.4707.gz with size 16kb. The corresponding postcript
file has gzipped size 104kb.
Submitted from: d.drivaliaris(a)fme.aegean.gr
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This is an announcement for the paper "Approximating with Gaussians"
by Craig Calcaterra and Axel Boldt.
Abstract: Linear combinations of translations of a single Gaussian,
e^{-x^2}, are shown to be dense in L^2(R). Two algorithms for determining
the coefficients for the approximations are given, using orthogonal
Hermite functions and least squares. Taking the Fourier transform of
this result shows low-frequency trigonometric series are dense in L^2
with Gaussian weight function.
Archive classification: math.CA math.FA
Mathematics Subject Classification: 41A30; 42A32; 42C10
Remarks: 16 pages, 23 figures
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gzipped form as 0805.3795.tar.gz with size 202kb. The corresponding
postcript file has gzipped size 279kb.
Submitted from: axel.boldt(a)metrostate.edu
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This is an announcement for the paper "On distribution and almost
convergence of bounded sequences" by Chao You and Bao Qi Feng.
Abstract: In this paper, we give the concepts of properly distributed
and simply distributed sequences, and prove that they are almost
convergent. Basing on these, we review the work of Feng and Li
[Feng, B. Q. and Li, J. L., Some estimations of Banach limits,
J. Math. Anal. Appl. 323(2006) No. 1, 481-496. MR2262220 46B45 (46A45).],
which is shown to be a special case of our generalized theory.
Archive classification: math.FA math.GM
Mathematics Subject Classification: Primary 40G05, 46A35, 54A20;
Secondary 11K36
Remarks: 8 pages
The source file(s),
Ondistributionandalmostconvergenceofboundedsequences.tex: 25039 bytes,
is(are) stored in gzipped form as 0805.3950.gz with size 8kb. The
corresponding postcript file has gzipped size 68kb.
Submitted from: hityou1982(a)gmail.com
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http://front.math.ucdavis.edu/0805.3950
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This is an announcement for the paper "On the nontrivial projection
problem" by Stanislaw J. Szarek and Nicole Tomczak-Jaegermann.
Abstract: The Nontrivial Projection Problem asks whether every
finite-dimensional normed space of dimension greater than one admits a
well-bounded projection of non-trivial rank and corank or, equivalently,
whether every centrally symmetric convex body (of arbitrary dimension
greater than one) is approximately affinely equivalent to a direct product
of two bodies of non-trivial dimension. We show that this is true "up
to a logarithmic factor."
Archive classification: math.FA
Mathematics Subject Classification: 46B20, secondary 46B07, 52A21
Remarks: 17 pages
The source file(s), NPPforArxiv.tex: 46100 bytes, is(are) stored in
gzipped form as 0805.3792.gz with size 17kb. The corresponding postcript
file has gzipped size 126kb.
Submitted from: szarek(a)cwru.edu
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This is an announcement for the paper "Simultaneous realization of
function space structures in transitive Banach spaces" by Fernando
Rambla and Jarno Talponen.
Abstract: Let L be a locally compact Hausdorff space and m the Lebesgue
measure on the unit interval. We will prove the existence of a transitive
Banach space X such that C_{0}(L,X) and the Bochner spaces L^{p}(m,X),
1\leq p\leq \infty, are all isometrically isomorphic to X. Also, more
general results of this type are presented.
Archive classification: math.FA
Mathematics Subject Classification: 46B04; 46E40
The source file(s), BCO4.tex: 52768 bytes, is(are) stored in gzipped
form as 0805.3616.gz with size 15kb. The corresponding postcript file
has gzipped size 96kb.
Submitted from: talponen(a)cc.helsinki.fi
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This is an announcement for the paper "The least singular value of a
random square matrix is O(n^{-1/2})" by Mark Rudelson and Roman Vershynin.
Abstract: Let A be a matrix whose entries are real i.i.d. centered random
variables with unit variance and suitable moment assumptions. Then
the smallest singular value of A is of order n^{-1/2} with high
probability. The lower estimate of this type was proved recently by the
authors; in this note we establish the matching upper estimate.
Archive classification: math.PR math.FA
Mathematics Subject Classification: 15A52
Remarks: 6 pages
The source file(s), square-matrices-reverse.tex: 17210 bytes, is(are)
stored in gzipped form as 0805.3407.gz with size 6kb. The corresponding
postcript file has gzipped size 68kb.
Submitted from: vershynin(a)math.ucdavis.edu
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This is an announcement for the paper "A note on James spaces and
superstrictly singular operators" by Isabelle Chalendar, Emmanuel Fricain,
and Dan Timotin.
Abstract: An elementary lemma is used in order to show that the natural
inclusion $J_p\to J_q$ of James spaces is superstrictly singular for
$p<q$. As a consequence, it is shown that an operator without nontrivial
invariant subspaces constructed by Charles Read is superstrictly singular.
Archive classification: math.FA
The source file(s), James.tex: 20594 bytes, is(are) stored in gzipped
form as 0805.3409.gz with size 7kb. The corresponding postcript file
has gzipped size 70kb.
Submitted from: fricain(a)math.univ-lyon1.fr
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Dear Colleagues,
We would like to invite you to participate in the summer school on
"Fourier analytic and probabilistic methods in geometric functional
analysis and convexity" in August 13-20, 2008.
The school is being organized by the NSF funded Focused Research Group
collaborative project on the same subject
(http://www.math.ucdavis.edu/~geofunction/). It is oriented towards
graduate students, postdocs and researchers who wish to get an
introduction to the subject. The school will feature several series's
of lectures. Confirmed speakers include
Alexander Barvinok (University of Michigan),
Piotr Indyk (Massachusetts Institute of Technology),
Fedor Nazarov (University of Wisconsin-Madison),
Krzysztof Oleszkiewicz (University of Warsaw),
Gideon Schechtman (Weizmann Institute of Scince),
Rolf Schneider (University of Freiburg),
Mikhail Sodin (Tel Aviv University),
Santosh S. Vempala (Georgia Institute of Technology).
The school will be hosted by the Department of Mathematical Sciences at
Kent State University in August 13-20, 2008 (Arrival date: August 12/
Departure Date August 21). Kent is located in the suburbs of Cleveland,
Ohio, where summers are quite beautiful.
For further information and breaking news, please, consult
http://www.math.kent.edu/math/FAPR.cfm
and e-mail to to Dmitry Ryabogin (ryabogin(a)math.kent.edu) or Artem
Zvavitch (zvavitch(a)math.kent.edu).
We hope to see you in Kent next August.
Best Regards,
The organizing committee
Alex Koldobsky
Mark Rudelson
Dmitry Ryabogin
Stanislaw Szarek
Roman Vershynin
Elisabeth Werner
Artem Zvavitch
This is an announcement for the paper "On unconditionally saturated
Banach spaces" by Pandelis Dodos and Jordi Lopez-Abad.
Abstract: We prove a structural property of the class of unconditionally
saturated separable Banach spaces. We show, in particular, that for every
analytic set $\aaa$, in the Effros-Borel space of subspaces of $C[0,1]$,
of unconditionally saturated separable Banach spaces, there exists
an unconditionally saturated Banach space $Y$, with a Schauder basis,
that contains isomorphic copies of every space $X$ in the class $\aaa$.
Archive classification: math.FA math.LO
Mathematics Subject Classification: 03E15, 46B03, 46B07, 46B15
Remarks: 16 pages, no figures. Studia Mathematica (to appear)
The source file(s), UnconditionallySaturated-ArXiv.tex: 49281 bytes,
is(are) stored in gzipped form as 0805.2046.gz with size 14kb. The
corresponding postcript file has gzipped size 102kb.
Submitted from: pdodos(a)math.ntua.gr
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