Max Dehn Seminar

on Geometry, Topology, Dynamics, and Groups

Academic year 2008 - 2009

Date Speaker Title — click for abstract (if available)
January 23, 2008 Christopher Cashen
University of Utah
Quasi-isometries between tubular groups
January 30, 2008 Christopher Cashen
University of Utah
Quasi-isometries between tubular groups, II
February 6, 2008 Dariusz Wilcznski
Utah State University
Composition Algebras and the Fundamental Theorem of Algebra for Polynomial Equations with a Tame Tail
February 13, 2008 Mladen Bestvina
University of Utah
Can higher rank lattices embed in Out(F_n)?
February 27, 2008 Benson Farb
University of Chicago
Analogies and contrasts between Riemann's moduli space and locally symmetric spaces
March 5, 2008 Yves de Cornulier
University of Rennes
Lie groups, their Dehn functions, and their asymptotic cones
April 2, 2008 Kevin Wortman
University of Utah
Cohomology of rank one arithmetic groups over function fields
April 10, 2008 Alexander Fel'shtyn
Boise State University
Groups with proerty R and twisted Burnside-Frobenius theorem
April 16, 2008 Daniel Allcock
University of Texas at Austin
The Hurwitz monodromy problem in degree 4
September 17, 2008 Mladen Bestvina
University of Utah
A hyperbolic Out(F_n)-complex, Part I
September 24, 2008 Mladen Bestvina
University of Utah
A New Proof of Morita's Theorem
October 3, 2008 Jean-Francois Lafont
The Ohio State University
A introduction to algebraic K-theory
October 8, 2008 Yael Algom Kfir
University of Utah
Negative curvature phenomena in outer space
October 22, 2008 Mladen Bestvina
University of Utah
A hyperbolic Out(F_n)-complex, Part II
November 12, 2008 Ken Bromberg
University of Utah
Convexity of length functions on Fenchel-Nielsen coordinates for Teichmüller space
November 29, 2008 Ian Biringer
University of Chicago
Geometry and rank of closed hyperbolic 3-manifolds
December 3, 2008 Julien Paupert
University of Utah
Discrete complex reflection groups in PU(2,1)
January 21, 2009 Kevin Wortman
University of Utah
Dehn functions of linear groups
January 28, 2009 Kevin Wortman
University of Utah
Dehn functions of linear groups II
February 4, 2009 Kai-Uwe Bux
University of Virginia
Thompson's group V is linear (or at least, it should be)
V has subgroups that are so close to being a BN-pair that the classical proof for simplicity of linear groups with irreducible Coxeter system goes through almost without change. It turns out that the subgroup F plays the role of the solvable Borel subgroup. [joint work with Jim Belk]
March 27, 2009 Martin Bridgeman
Boston College
Orthospectra of GEodesic Laminations
Given a measured lamination on a finite area hyperbolic surface we consider a natural measure M on the real line obtained by taking the push-forward of the volume measure of the unit tangent bundle of the surface under an intersection function associated with the lamination. We show that the measure M gives summation identities for the Rogers dilogarithm function on the moduli space of a surface.
April 9, 2009 Robert Young
The Dehn function of SL(n,Z)
The Dehn function is a group invariant which connects geometric and combinatorial group theory; it measures both the difficulty of the word problem and the area necessary to fill a closed curve in an associated space with a disc. The behavior of the Dehn function for high-rank lattices in high-rank symmetric spaces has long been an open question; one particularly interesting case is SL(n,Z). Thurston conjectured that SL(n,Z) has a quadratic Dehn function when n>=4. This differs from the behavior for n=2 (when the Dehn function is linear) and for n=3 (when it is exponential). In this talk, I will discuss some of the background of the problem and sketch a proof that the Dehn function of SL(n,Z) is at most quartic when n >= 5.
April 22, 2009 Natasa Macura
University of Utah/ Trinity University
April 30, 2009 Matt Stover
University of Texas at Austin
Volumes of Picard modular surfaces
Picard modular surfaces are the non-compact arithmetic complex hyperbolic 2-orbifolds. I will prove that the two orbifolds studied by John Parker as candidates for orbifolds of smallest volume are indeed the unique arithmetic complex hyperbolic 2-orbifolds of minimal volume. Given time, I will also make some remarks on finding minimal volume manifolds.
May 6, 2009 Valerio Pascucci
Scientific Computing and Imaging Institute, University of Utah
Multi-scale Morse Theory for Scientific Data Analysis
Advanced techniques for understanding large scale scientific data are a crucial ingredient in modern science discovery. Developing such techniques involves a number of major challenges in management of massive data, and quantitative analysis of scientific features of unprecedented complexity. Addressing these challenges requires interdisciplinary research in diverse topics including the mathematical foundations of data representations, algorithmic design, and the integration with applications in physics, biology, or medicine. In this talk, I will present a set of case in the use of Morse theory for the representation and analysis of large-scale scientific data. Due to the combinatorial nature of the approach, we can implement the core constructs of Morse theory without the approximations and instabilities of classical numerical techniques. We use topological cancellations to build multi-scale representations that capture local and global trends present in the data. The inherent robustness of our combinatorial algorithms allows us to address the high complexity of the feature extraction problem for high-resolution scientific data.

Current seminar          Archive of past talks
Max Dehn Seminar is organized by Mladen Bestvina, Ken Bromberg, Patrick Reynolds,
Jing Tao, Domingo Toledo, and Kevin Wortman.

This web page is maintained by Patrick Reynolds and Jing Tao.