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University of Georgia
Department of Mathematics

Seminar Schedule
March 6 – March 10, 2006

All Seminars are held in Boyd Graduate Studies Bldg. unless otherwise noted.

MONDAY, March 6, 2006

VIGRE-Algebraic Geometry
2:00pm, Room 304

Topology/Geometry
2:30pm Room 222
Speaker: Emily Hamilton (Emory)
Title: Iso-length spectral arithmetic hyperbolic 3-manifolds
Abstract: Let M be an orientable hyperbolic 3-manifold of finite volume.
The length spectrum of M is the collection of all lengths of closed geodesics in M counted with their multiplicities. The complex length spectrum of M is the collection of all complex lengths of closed geodesics in M counted with their multiplicities. Two orientable hyperbolic 3-manifolds of finite volume are called iso-length spectral (resp. complex iso-length spectral) if their length spectra (resp. complex length spectra) are identical. It is known that if M_1 and M_2 are complex iso-length spectral arithmetic hyperbolic 3-manifolds, then they are commensurable. We show that if M_1 and M_2 are iso-length spectral arithmetic hyperbolic 3-manifolds, then M_1 and M_2 are commensurable.

3:45 Boyd 222
Speaker: Chris Leininger (UIUC)
Title: Pseudo-Anosov dilatations and algebra
Abstract: The dilatation of a pseudo-Anosov homeomorphism F of a closed surface S_g of genus g is a basic measure of its dynamical complexity. Penner proved that if one allows g to tend to infinity, then the logarithm of the smallest possible dilatation of such a homeomorphism tends to zero on the order of 1/g. I'll discuss joint work with Benson Farb and Dan Margalit that describes how this type of behavior is prohibited if one imposes certain algebraic restrictions. As the simplest example, we prove that if F acts trivially on homology, then the logarithm of its dilatation is bounded below by .098 (independent of g). I'll also describe how this is sharply contrasted when one considers a natural measure of topological complexity.

Algebra
2:30pm, Room 410
Speaker: Bobbe Cooper, University of Georgia
Title of talk: Support Varieties for Tilting Modules
Abstract: Let $G$ be a reductive algebraic group of type A_n over an algebraically closed field $k$ of characteristic $p>0$, with Frobenius kernel $G_1$. The tilting modules of $G$ are defined as modules for which both the module itself and its dual have good filtrations. In this talk, the support varieties of these modules over $G_1$ will be calculated. This calculation (probably) confirms for type A_n Humphrey's conjecture for the supports of tilting modules.

Faculty and Graduate Student Social
3:00pm, Room 409
Coffee, Cookies, Tea


TUESDAY, March 7, 2006

VIGRE-Graduate Student Seminar
2:00p.m., Room 304
Speaker: Emille Davie, University of Georgia
Title of talk: TBA


WEDNESDAY, March 8, 2006

VIGRE Site Visit
8:00am-4:15pm

Geometry in the Curriculum Seminar
1:25pm, Aderhold, Room 111
Speakers: Tom Banchoff and Clint McCrory, University of Georgia
Title of talk: Plans for the workshop "Geometry Across the Curriculum" on March 25 at the Georgia Center

Algebraic Geometry
2:30pm, Room 302
No meeting this week

VIGRE- Algebra
2:30pm, Room 303
No meeting this week

Faculty and Graduate Student Social
3:15pm, Room 409
Cookies, Coffee, Tea

Arithmetic Geometry/Number Theory
4:00pm, Room 304
Speaker: Robert Rumely, University of Georgia
Title of talk: Multi-resultants and the Fekete-Leja Transfinite Diameter, continued


THURSDAY, March 9, 2006

VIGRE – Feynman Diagrams
2:00pm, Room 326

VIGRE – Cardiac Physiology
2:00pm, Room 640

VIGRE- Zeta Functions
2:15pm, Room 302

VIGRE-Algebraic Geometry
2:00pm, Room 304

FRIDAY, March 10, 2006

Probability Theory
2:30-3:30pm, Room 303
Speaker: L. Yu, University of Georgia
Title of talk: Piecewise non-linear filter (cont.)