Tuesday
September 08
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Location: NDSU
Refreshments at 3:30 PM in Minard 303C (Math Lounge)
Talk at 4:00 PM in Minard 136
Title:
Noncommutative Topology
Speaker:
Benton Duncan, NDSU
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Abstract:
A common heurisitic in the C^*-algebra world is to view C^*-algebras as
continuous functions on noncommutative "spaces". We will discuss where
this idea comes from as well as discuss some examples of this heuristic in
action.
I intend for this talk to be accessible for even the newest graduate
students and yet to provide some depth for faculty in attendance.
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Tuesday
September 15
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No colloquium.
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Tuesday
September 22
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No colloquium.
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Tuesday
September 29
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Location: NDSU
Refreshments at 3:30 PM in Minard 303C (Math Lounge)
Talk at 4:00 PM in Minard 136
Title:
Mathematics and Recovery of the Bald Eagle
Speaker:
James W. Grier, Emeritus Professor, NDSU Department of Biological Sciences
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Abstract:
The bald eagle, national symbol of the US, was rapidly declining in numbers by the 1960s on a path toward extinction. Bald Eagle Recovery Teams were established by the US Fish and Wildlife Service to study the problems and recommend solutions. Jim Grier was nominated chair of the Northern States recovery team, covering a 25 state area. Much of the solution and subsequent recovery of the species hinged on understanding eagle population dynamics. Jim developed the mathematical population simulation models (during the 1970s, at an early stage of modern computing techniques) that played a role in the species' recovery. Following an introduction about the bald eagle and how eagle population data are obtained, he will discuss simulation life tables and the individual-based deterministic and stochastic models that he developed. The presentation is intended to be accessible to graduate and undergraduate students in math (as well as other students who are interested in math).
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Tuesday
October 6
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Location: NDSU
Refreshments at 3:30 PM in Minard 303C (Math Lounge)
Talk at 4:00 PM in Minard 136
Title:
Optimal Geometry Distortion of Diffeomorphisms between Manifolds
Speaker:
Oksana Bihun, Concordia
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Abstract:
The problem of mapping of surfaces with minimal distortion of geometry
arises in medical imaging, animation, and industry. While there is an
extensive literature on numerical methods that lead to a small distortion
map, the underlying mathematical problem is not well understood.
Each diffeomorphism h between two compact smooth n-manifolds M and N
distorts the geometry of M in a certain way. We ask which diffeomorphisms
produce the least distortion and introduce cost functionals that measure
the distortion. The functional G(h)=\int_M J(h)^2, where J(h) is the
Jacobian determinant of h, measures the distortion with respect to the
change of volume. If the manifolds M and N are Riemannian with the metrics
g_M and g_N respectively, the functional F(h)= \int_M ||h*g_N-g_M||^2
measures the distortion due to strain; the minimizers of F are approximate
isometries. We also consider functionals that measure distortion due to
bending. We employ some important results on volume forms on manifolds,
linearization via time dependent vector fields, some evolution operator
theory, and methods of calculus of variations, to prove the existence of
minimizers of the above cost functionals in certain classes of
diffeomorphisms. We generalize our findings to the problem of minimal
distortion morphing (through homotopies) of compact manifolds.
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Tuesday
October 13
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No colloquium.
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Tuesday
October 20
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Location: NDSU
Refreshments at 3:30 PM in Minard 303C (Math Lounge)
Talk at 4:00 PM in Minard 136
Title:
Some Remarks on Atomic, Purgatory, and Antimatter domains
Speaker:
Travis Trentham, NDSU
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Abstract:
A nonzero nonunit element p in an integral domain D is said to
be an atom (irreducible) provided that given any factorization p=xy in D,
then either x or y is a unit of D. If every nonzero nonunit in D can be
expressed as a product of atoms, then D is said to be atomic. Should D
fail to admit any atoms, then we say that D is an antimatter domain.
However, there are also domains which fail to be either atomic or
antimatter. We shall call any such domain a purgatory domain. In this
talk we shall consider some examples from each of these three classes and
discuss how they might present themselves in the theory of factorization.
We shall also present a problem addressing the relative abundance of these
types of rings and look at some progress that has been made on this
problem.
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Tuesday
October 27
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No colloquium.
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Thursday
November 05
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Location: NDSU
Refreshments at 3:30 PM in Minard 303C (Math Lounge)
Talk at 4:00 PM in Morrill 109. Note the different day and location!
Title:
The Beurling-Selberg Extremal Problem
Speaker:
Emanuel Carneiro, Institute for Advanced Study
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Abstract:
I will describe the classical theory and recent developments on
the Beurling-Selberg problem of approximating real-valued functions by
entire functions of prescribed exponential type, and discuss several
applications of these approximations to number theory. The recent results
are part of a joint program with Friedrich Littmann (NDSU) and Jeffrey D.
Vaaler (Texas - Austin).
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Tuesday
November 10
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Location: NDSU
Refreshments at 3:30 PM in Minard 303C (Math Lounge)
Talk at 4:00 PM in Minard 136
Title:
Equivariant Intersection Rings
Speaker:
Damiano Fulghesu, University of Strasbourg
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Abstract:
An equivariant intersection theory has been developed for smooth algebraic schemes acted
on by an algebraic group. However the computation of intersection rings with integer
coefficients is usually challenging. Some interesting results can be obtained when we
consider actions by GLn of an open subset of a representation. These techniques allow to
explicit intersection rings of some moduli stacks of curves.
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Tuesday
November 17
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Location: MSUM
Refreshments at 4:00 in Maclean 167
Talk at 4:30 PM in Maclean 167. Note the different time!
Title:
Using Mathematics to Create Symmetry Patterns
Speaker:
Joseph A. Gallian - University of Minnesota Duluth
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Abstract:
We use video animations to illustrate how mathematics can be used to
create computer generated symmetry patterns. Polynomials,
exponential functions, logarithms and modular arithmetic are used to
transform basic images into symmetry patterns. These methods were
used to create the image for the 2003 Mathematics Awareness Month poster.
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Tuesday
November 24
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No colloquium.
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Tuesday
December 01
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Location: NDSU
Refreshments at 3:30 PM in Minard 303C (Math Lounge)
Talk at 4:00 PM in Minard 136
Title:
TBA
Speaker:
Rob Hladky, NDSU
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Abstract:
TBA
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Tuesday
December 08
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No colloquium.
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