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Past schedules:
August08|September08|October08|November08|December08|January09|February09|March09|April09|
May09|June09|July09|
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AUGUST 2009
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Thursday, August 6
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Thesis Defense
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Time: 3:00-5:00pm
Location: Cupples I, Room 199
Host: Profs. Guido Weiss and Edward Wilson
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Speaker: Robert Houska
Department of Mathematics, Washington University in St. Louis
Title: Frames, Composite Wavelets, and Shearlets
Abstract: One-dimensional wavelet systems have enjoyed a great deal of
success in
applications. This success is due, in large part, to the plentiful
existence of compactly supported and smooth one-dimensional scaling
functions.
Traditional wavelet systems have been used quite successfully in
higher-dimensional applications as well. However, the geometric structure
present in dimensions two and higher is significantly more complex than
that present in dimension one, and there are several important
multi-dimensional applications for which traditional wavelet systems are
too geometrically simplistic. In response to this deficiency, the more
geometrically diverse composite wavelet systems were recently introduced
by Guo, Labate, Weiss, and Wilson.
A particular type of composite wavelet system - the shearlet system - has
been shown by the above mentioned authors to outperform traditional
wavelet systems in several important multi-dimensional applications.
Despite these positive results, however, shearlet systems have one major
drawback - essentially no useful shearlet scaling functions exist. We will
discuss several results of this variety.
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Thursday, August 27
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Thesis Defense
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Time: 1:30-3:30pm
Location: Cupples I, Room 199
Host: Prof. Rachel Roberts
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Speaker: Michael Hamm
Washington University in St. Louis
Title: Filling Essential Laminations
Abstract: Thurston and, later, Calegari-Dunfield found superlaminations in certain lamniated
3-manifolds, the existence of which implies inclusions into HomeoS1 of the
fundamental groups of those manifolds. The present paper extends the construction
of the superlamination, and finds an infinite class of manifolds to which the extension
does not yield such an inclusion of groups.
Specifically, Calegari and Dunfield’s proof of the existence of such an inclusion
into HomeoS1 depended on their filling lemma, which states that essential laminations
with solid torus guts can have leaves added to them to yield essential laminations with
solid torus complementary regions. (Roughly, a gut is that part of a complementary
region that is not sandwiched between only two leaves.) The present paper finds the
leafspace of the resultant lamination, and extends Calegari and Dunfield’s operation
to more general cases: first to reduce any finite-genus-handlebody complementary
region to its gut, and then to reduce the genus of a complementary region even where
doing so modifies the gut itself. In these cases, too, then, there can be an inclusion
of the manifold’s fundamental group into HomeoS1.
Cataclysms correspond to non-Hausdorffness in the leafspace of a lamination. A
cataclysm is orderable if some order on it is invariant under deck transformations.
Calegari-Dunfield showed that orderability of cataclysms, which is weaker than Hausdorffness
of the leafspace, is sufficient for the existence of an inclusion into HomeoS1.
The present paper finds a criterion for the non-orderability of cataclysms, and a class
of examples satisfying the criterion.
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Thursday, August 27
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Colloquium
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Time:Tea: 4:00-4:30pm
Talk: 4:30-5:30pm
Location: Cupples I, Room 199
Host: Prof. Jack Shapiro
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Speaker: Professor Jack Sonn
The Technion, Haifa, Israel
Title: The
minimal ramification problem in Galois theory
Abstract: The minimal ramification problem is a refinement of the
inverse Galois problem. Can every finite group G be realized as a
Galois group over the rational numbers with the minimal possible
number of ramified primes? This minimal possible number is
essentially the minimal number of conjugacy classes that generate
G. For example, if G is the symmetric group S_n, then this number
is 1, and the problem is still open except for a few small values
of n. For finite nilpotent groups G this number coincides with
the minimal number of generators of G. It has recently been proved
that
this problem has an affirmative answer for a substantial class of
finite nilpotent groups (all finite semiabelian nilpotent groups).
(Joint work with Hershy Kisilevsky and Daniel Neftin)
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FALL 2009 Seminars Schedule
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Mondays
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Analysis Seminar
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Time: 4:00-5:00pm *
Location: Cupples I, Room 199
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Host: Prof. Richard Rochberg
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Wednesdays
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Algebraic Geometry Seminar
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Time: 4:00-5:30pm *
Location: Cupples I, Room 215
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Host: Prof. Mohan Kumar
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Thursdays
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Geometry and Topology Seminar
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Time: 3:00-4:00pm *
Location: Cupples I, Room 111
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Host: Prof. Xiang Tang
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Fridays
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Wavelet Seminar
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Time: 3:30-4:30pm *
Location: Cupples I, Room 199
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Host: Prof. Guido Weiss
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* Times may vary, please consult the schedule below for details:
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SEPTEMBER 2009
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Friday, September 4
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Wavelet Seminar
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Time: 3:30-4:30pm
Location: Cupples I, Room 199
Host: Prof. Guido Weiss
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Speaker: Professor Joe Lakey
Department of Mathematics, Washington University in St. Louis
Title: Gabor window functions and their Zak transforms
Abstract: The talk will be expository. It will point out the role that
the Zak transform can play in determining represenation and convergence
properties of Gabor expansions.
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Monday, September 14
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Analysis Seminar
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Time: 4:00-5:00pm
Location: Cupples I, Room 199
Host: Prof. Richard Rochberg
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Speaker: Prof. Richard Rochberg
Department of Mathematics, Washington University in St. Louis
Title: Organization of the Seminar
Abstract:This will be a brief meeting to organize the seminar for the semester
and do preliminary scheduling.
If you are interested in participating in the seminar and can't make
this meeting please let me know.
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Thursday, September 17
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Geometry and Topology Seminar
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Time: 3:00-4:00pm
Location: Cupples I, Room 111
Host: Prof. Xiang Tang
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Speaker: Professor Xiang Tang
Department of Mathematics, Washington University in St. Louis
Title: Organization of the Seminar
Abstract: We will discuss the plan of the semester. Everybody interested in
geometry and topology is welcome to join us.
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Thursday, September 24
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Colloquium
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Time: Tea: 4:00-4:30pm
Talk: 4:30-5:30pm
Location: Cupples I, Room 199
Host: Prof. Xiang Tang
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Speaker: Professor Nigel Higson
Department of Mathematics, Penn State
Title: C*-algebras and the parametrization of irreducible group representations
Abstract: C*-algebras were invented, in part, as a tool to address the unitary
representation theory of Lie groups. However close associations
between C*-algebra theory and representation theory more or less ended
in the 1950's, in the infancy of both fields. A reconciliation of
sorts began in the 1980's with the development of new C*-algebra
methods inspired by the Atiyah-Singer index theorem. I shall try to
present one aspect of this: an approach to parametrizing the tempered
irreducible representations of a semisimple group using its so-called
Cartan motion group.
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Wednesday, September 30
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Colloquium
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Time: Tea: 4:00-4:30pm
Talk: 4:30-5:30pm
Location: Cupples I, Room 199
Host: Prof. Roya Beheshti-Zavareh
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Speaker: Professor Joseph Landsberg
Department of Mathematics, Texas A&M
Title: TBA
Abstract: TBA
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NOVEMBER 2009
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Wednesday, November 4
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Colloquium
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Time: Tea: 4:00-4:30pm
Talk: 4:30-5:30pm
Location: Cupples I, Room 199
Host: Prof. Roya Beheshti-Zavareh
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Speaker: Professor Dragos Oprea
Department of Mathematics, University of California, San Diego
Title: TBA
Abstract: TBA
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SPRING 2010 Seminars Schedule
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APRIL 2010
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Thursday, April 22, 2010
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Loeb Lecture
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Time: Tea: 4:00-4:30pm
Talk: 4:30-5:30pm
Location: TBA
Host: Prof. Ronald Freiwald
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Speaker: Professor Martin Golubitsky
Department of Mathematics, Ohio State University
Title: TBA
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