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Spring Semester 2009
This spring’s talks are organized
into a mini-conference that will meet on Saturday, March 21, 2009
All talks will be on the second floor of Pardee Hall at
Schedule of Events: There will be coffee
and snacks at 9:30, with talks starting at 10:00. Lunch is provided, and the seminar will
end around 3:00
|
9:30 – 10:00 |
Coffee and snacks |
|
|
10:00 – 10:50 |
Jie Qing (UCSC, currently at IAS) |
Title: Finiteness
and gap theorems in conformal geometry Abstract: We will
discuss a diffeomorphism finiteness and gap theorem
for Bach flat 4-manifolds in conformal geometry. Following the idea in the finiteness
theorem of Anderson and Cheeger, our theorem is based
on a construction of a bubble tree of the degeneration of metrics. |
|
11:00 – 11:50 |
Anna Wienhard ( |
Title: Domains of
discontinuity for Anosov representations Abstract: Let Γ be the fundamental group of
a closed surface of genus g ≥ 2 and ρ: Γ → G a representation into a semisimple
Lie group. When does there exists
a parabolic subgroup P and a
non-empty open subset Ω in G/P such that Γ acts properly
discontinuously on Ω with compact quotient? A positive answer to this question was known for some
special classes of representations, e.g. quasi-Fuchsian
representations of Γ into PSL(2,C) or convex representations into PSL(3,R). We construct such domains of discontinuity for a much
bigger class of representations, so-called Anosov
representations, which are characterized by certain dynamical properties.
This class includes in particular all “higher” Teichmüller spaces. This is joint work with Olivier Guichard. |
|
12:00 – 1: 00 |
Lunch (provided) |
|
|
1:10 – 2:00 |
Lucas Sabalka ( |
Title: Generalized
Expanders Abstract: Tessera and Ostrovskii have independently introduced a generalized
notion of expander in terms of probability measures on metric spaces.
In joint work with Jerry Kaminker, we analyze
certain classes of these generalized expanders. In this context we
study, among other results, the obstruction to being able to uniformly embed
a metric space into a Hadamard manifold. |
|
2:10 – 3:00 |
Dave Futer ( |
Title: The geometry of unknotting tunnels In the generic situation where the complement of K is hyperbolic, we can ask a number
of geometric questions about the tunnel. The following questions have been
open since the mid 1990s: Is τ isotopic to a geodesic? Is it isotopic to
an edge of the canonical triangulation? Can τ be arbitrarily long? I will present some recent work, joint with Jessica Purcell,
that answers these three questions if the knot K is created by long Dehn filling. |
Past seminar
schedules:
For further information, contact Ethan Berkove at berkovee at lafayette dot edu.
[ Lafayette Math
Dept ] [ Lehigh
Math Dept ]