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PRODID:-//Mathematics Department//NONSGML mathical.php//EN
X-WR-CALNAME:Mathematics Department
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb117b@math.dartmouth.edu
DTSTART;TZID=America/New_York:20170914T143000
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:John Voight: Adelic integration and the Riemann zeta
function
LOCATION:Kemeny 343
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb1468@math.dartmouth.edu
DTSTART;TZID=America/New_York:20170915T153000
CATEGORIES:Math Colloquium
SUMMARY:Joan Richards: Mathematics and its Rigors
DESCRIPTION:The "rigor that is often seen as the definition of
mathematical thinking is a relatively modern concept. This talk will
use several incidents that took place in France and England in the
eighteenth and nineteenth centuries to highlight some of the
issues\, concerns and forces that underly the understanding of
mathematics as a rigorous subject in the twentieth and twenty-first
centuries.
LOCATION:007 Kemeny Hall
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb1752@math.dartmouth.edu
DTSTART;TZID=America/New_York:20170921T143000
DTEND;TZID=America/New_York:20170921T153000
CATEGORIES:Algebra and Number Theory Seminar
SUMMARY:John Voight: Adelic integration and the Riemann zeta
function\, II
LOCATION:Kemeny 343
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb1a17@math.dartmouth.edu
DTSTART;TZID=America/New_York:20170922T153000
CATEGORIES:Math Colloquium
SUMMARY:Michael J. Barany: Confused Distinctions: The Secret History
of the pre-1960 Fields Medal
DESCRIPTION:First presented in 1936\, the Fields Medal quickly
became one of mathematicians' most prestigious\, famous\, and in
some cases notorious prizes. Because its deliberations are
confidential\, we know very little about the early Fields Medals:
how winners were selected\, who else was considered\, what values
and priorities were debated---all these have remained locked in
hidden correspondence. Until now.\n\nMy talk will analyze newly
discovered letters from the 1950 and 1958 Fields Medal committees\,
which I claim demand a significant change to our understanding of
the pre-1960 medals. I will show\, in particular\, that the award
was not considered a prize for the very best mathematicians\, or
even for the very best young mathematicians. Debates from those
years also shed new light on how the age limit of 40 came about\,
and what consequences this had for the Medal and for the mathematics
profession.
LOCATION:007 Kemeny Hall
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb1d24@math.dartmouth.edu
DTSTART;TZID=America/New_York:20170926T160000
CATEGORIES:Geometry and Topology Seminar
SUMMARY:Petra Bonfert-Taylor: Quasiconformal Homogeneity\, Active
Learning and Programming
DESCRIPTION:Abstract: What do the seemingly distinct topics in the
title have to do with one another? They are all tied together via
the active learning piece. If you don’t know what active learning
is\, you’ll find out in this talk. Ditto for quasiconformal
homogeneity. And while you probably know all about programming\,
I’ll demonstrate some novel tools we are developing at Thayer to
facilitate active learning in a programming class.\n\nQuasiconformal
Homogeneity: A quasiconformal homeomorphism between domains is a
mapping that behaves as much like a conformal mapping as possible in
that\, infinitesimally\, it distorts spheres at worst into
ellipsoids with bounded ratio between major and minor axes. A domain
is quasiconformally homogeneous if any two of its points can be
mapped onto one another via a quasiconformal homeomorphism of the
domain to itself. I’ll speak about geometric and topological
constraints that quasiconformal homogeneity imparts on domains (or\,
more generally\, hyperbolic manifolds) and attempts to classify
them. The audience will be involved in this presentation.
LOCATION:TBA
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb2023@math.dartmouth.edu
DTSTART;TZID=America/New_York:20170929T153000
CATEGORIES:Math Colloquium
SUMMARY:Nathanial Brown: TBA
LOCATION:Kemeny 007
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb220c@math.dartmouth.edu
DTSTART;TZID=America/New_York:20171006T153000
CATEGORIES:Math Colloquium
SUMMARY:Alexandre Girouard: Isoperimetric problems in spectral
geometry
DESCRIPTION:Spectral geometry is a young 50 year old branch of
mathematics which is developing rapidly. It blends together
differential geometry\, partial differential equations\, and
analysis. To a large extent it is motivated by questions
originating in the study of real-life phenomena\, such as
vibrations\, oscillations of fluids\, and quantum mechanics. This
subject studies the links between the geometry of a space and the
eigenvalues of a (pseudo)differential operator acting on functions
of that space. In this talk I will be interested in two operators:
the Laplace-Beltrami operator and the Dirichlet-to-Neumann map. My
goal will be to overview the isoperimetric properties of their
eigenvalues. Despite sharing many common features\, we will see that
these two operators are also drastically different from the point of
view of isoperimetric control.
LOCATION:007 Kemeny Hall
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb242a@math.dartmouth.edu
DTSTART;TZID=America/New_York:20171013T150000
CATEGORIES:Math Colloquium
SUMMARY:Franco Saliola: Spectral analysis of random-to-random Markov
chains
DESCRIPTION:"Pick a card (any card)\, remove it and put it back
anywhere in the deck." Repeating this process defines a card
shuffling technique known as the random-to-random shuffle. A natural
question to ask of any shuffling technique is how many shuffles are
needed to randomize the deck of cards. This is controlled by the
spectra of the associated transition matrices.\n\nBy considering all
the random-to-random shuffles simultaneously\, we prove that the
eigenspaces admit a beautiful recursive structure. This structure
allows one to build eigenbases starting from bases for the kernels.
Among other things\, we obtain complete combinatorial descriptions
of the eigenvalues of the transition matrices. The representation
theory of the symmetric group features prominently in our analysis\,
but the results and the talk can be appreciated with no prior
knowledge of representation theory.\n\nThis talk is based on joint
work with Ton Dieker (Columbia University).
LOCATION:007 Kemeny Hall
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb264d@math.dartmouth.edu
DTSTART;TZID=America/New_York:20171027T153000
CATEGORIES:Math Colloquium
SUMMARY:Liliana Borcea: Untangling the nonlinearity in inverse
scattering using data-driven reduced order models
DESCRIPTION:We discuss an inverse problem for the wave equation\,
where an array of sensors probes an unknown\, heterogeneous medium
\nwith pulses and measures the scattered waves. The goal in
inversion is to determine from these measurements scattering
structures \nin the medium\, modeled mathematically by a
reflectivity function. Most imaging methods assume a linear mapping
between the \nunknown reflectivity and the array data. The
linearization\, known as the Born (single scattering) approximation
is not accurate in \nstrongly scattering media\, so the
reconstruction of the reflectivity may be poor. We show that it is
possible to remove the multiple \nscattering (nonlinear) effects
from the data using a reduced order model (ROM). The ROM is defined
by an orthogonal projection\nof the wave propagator operator on the
subspace spanned by the time snapshots of the solution of the wave
equation. The snapshots are \nknown only at the sensor locations\,
which is enough information to construct the ROM. The main result
discussed in the talk is a \nnovel\, linear-algebraic algorithm that
uses the ROM to map the data to its Born approximation.
LOCATION:007 Kemeny Hall
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb287e@math.dartmouth.edu
DTSTART;TZID=America/New_York:20171103T153000
CATEGORIES:Math Colloquium
SUMMARY:Henry Segerman: Design of 3D printed mathematical art
DESCRIPTION:When visualising topological objects via 3D printing\,
we need a three-dimensional geometric representation of the object.
There are approximately three broad strategies for doing this:
"Manual" - using whatever design software is available to build the
object by hand\; "Parametric/Implicit" - generating the desired
geometry using a parametrisation or implicit description of the
object\; and "Iterative" - numerically solving an optimisation
problem.\n\nThe manual strategy is unlikely to produce good results
unless the subject is very simple. In general\, if there is a
reasonably canonical geometric structure on the topological object\,
then we hope to be able to produce a parametrisation of it.
However\, in many cases this seems to be impossible and some form of
iterative method is the best we can do. Within the parametric
setting\, there are still better and worse ways to proceed. For
example\, a geometric representation should demonstrate as many of
the symmetries of the object as possible. There are similar issues
in making three-dimensional representations of higher dimensional
objects. I will discuss these matters with many examples\, including
visualisation of four-dimensional polytopes (using orthogonal versus
stereographic projection) and Seifert surfaces (comparing my work
with Saul Schleimer with Jack van Wijk's iterative techniques).\n\nI
will also describe some computational problems that have come up in
my 3D printed work\, including the design of 3D printed mobiles
(joint work with Marco Mahler)\, "Triple gear" and a visualisation
of the Klein Quartic (joint work with Saul Schleimer)\, and hinged
surfaces with negative curvature (joint work with Geoffrey Irving).
LOCATION:007 Kemeny Hall
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb2abc@math.dartmouth.edu
DTSTART;TZID=America/New_York:20171110T153000
CATEGORIES:Math Colloquium
SUMMARY:Nicholas Scoville: $S^1$ and $S^3$ and $S^2$\, oh fi! A
digital Hopf fibration
DESCRIPTION:Digital images surround us. They are found in our
computers\, iPhones\, televisions\, and more. Because they are so
integrated into our lives\, there is a constant need to manipulate
and investigate these images. Anything that one might want to do
with a digital image will inevitably involve some kind of
mathematics\, whether it be linear algebra\, geometry\, or topology.
To that end\, we will introduce topology in the digital setting\,
noting some places where it is similar and different than in the
smooth setting. In particular\, we will work with digital homotopy
between digital images by viewing a digital image as a tolerance
space\, which sits inside of a well-defined category. Although
there is a notion of digital fibration in this context\, there seem
to be very few non-trivial examples of digital fibrations. We will
construct a digital analogue of the Hopf fibration\, the most
important single example in the history of algebraic topology.
Because the $3$-sphere in this setting consists of only $24$
pixels\, this example is robust yet small enough to be written down
and investigated explicitly. This talk will be accessible to
undergraduates.
LOCATION:007 Kemeny Hall
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb2ce3@math.dartmouth.edu
DTSTART;TZID=America/New_York:20180223T153000
CATEGORIES:Math Colloquium
SUMMARY:Tony Várilly-Alvarado: TBA
LOCATION:Kemeny 007
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb2ed4@math.dartmouth.edu
DTSTART;TZID=America/New_York:20180302T153000
CATEGORIES:Math Colloquium
SUMMARY:Graduate Open House\, Faculty Talks: TBA
LOCATION:Kemeny 007
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb30b9@math.dartmouth.edu
DTSTART;TZID=America/New_York:20180406T153000
CATEGORIES:Math Colloquium
SUMMARY:Tatiana Roque: TBA
LOCATION:Kemeny 007
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb3283@math.dartmouth.edu
DTSTART;TZID=America/New_York:20180413T153000
CATEGORIES:Math Colloquium
SUMMARY:Norbert A'Campo: TBA
LOCATION:Kemeny 007
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb3471@math.dartmouth.edu
DTSTART;TZID=America/New_York:20180418T180000
CATEGORIES:Kemeny Lecture
SUMMARY:Martin Nowak: TBA
LOCATION:Kemeny 008
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb365d@math.dartmouth.edu
DTSTART;TZID=America/New_York:20180419T153000
CATEGORIES:Kemeny Lecture
SUMMARY:Martin Nowak: TBA
LOCATION:Kemeny 008
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb3848@math.dartmouth.edu
DTSTART;TZID=America/New_York:20180420T153000
CATEGORIES:Kemeny Lecture
SUMMARY:Martin Nowak: TBA
LOCATION:Kemeny 008
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb3a34@math.dartmouth.edu
DTSTART;TZID=America/New_York:20180427T153000
CATEGORIES:Math Colloquium
SUMMARY: Yun Kang: TBA
LOCATION:Kemeny 007
END:VEVENT
BEGIN:VEVENT
DTSTAMP:20170920T071701Z
UID:20170920T03170159c215edb3c22@math.dartmouth.edu
DTSTART;TZID=America/New_York:20180518T153000
CATEGORIES:Math Colloquium
SUMMARY:David Roberts: TBA
LOCATION:Kemeny 007
END:VEVENT
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