Events
| << Prev | November 02, 2009 - November 09, 2009 | Next >> |
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Mon 11/2
Aspects of Hurwitz numbers (Invitation to Research)
Hsian-Hua Tseng (OSU)
Start: 4:30 am
End: 5:30 am
Location: CH 240
CH 240
Holomorphic QUE for Hilbert modular varieties (Number Theory Seminar)
Simon Marshall (Princeton University)
Start: 4:30 pm
End: 5:30 pm
Location: MW 154
MW 154
Recently, Holowinsky and Soundararajan have proven that the L^2 mass of a sequence of holomorphic Hecke eigenforms of large weight on SL(2,Z) becomes equidistributed, settling a case of the quantum unique ergodicity conjecture of Rudnick and Sarnak. I will present a generalization of their work to holomorphic forms on noncompact Hilbert modular varieties over any totally real field, or more generally, automorphic forms of cohomological type on GL(2) over any number field. I will also give an application of the result in the holomorphic case to the equidistribution of zero divisors of modular forms. | ||
Tue 11/3
Inverse square potentials and applications to general relativity (Real and Complex Analysis Seminar)
Wilhelm Schlag (University of Chicago)
Start: 2:30 pm
End: 3:20 pm
Location: MW154
MW154
We will discuss recent work on the problem of proving pointwise decay in Multi-gradient schemes arising from local systems (Algebraic Geometry Seminar)
Yu-Han Liu (OSU)
Start: 4:30 pm
End: 5:30 pm
Location: N050, Scott Lab
N050, Scott Lab
It is known that the Noether-Lefschetz loci on Calabi-Yau threefolds are gradient schemes. We formalize its proof to systematically produce many examples of multi-gradient schemes.
Singular Shocks and Loss of Hyperbolicity in Conservation Laws (Partial Differential Equations Seminar)
Barbara Lee Keyfitz (OSU)
Start: 4:30 pm
End: 5:30 pm
Location: EA265
EA265
Singular shocks, or solutions of very low regularity to systems of conservation laws, were first described in the 1980's by Herbert Kranzer and myself. They appeared in solving Riemann problems with large data in a strictly hyperbolic system of two conservation laws, and appeared to be a mere curiosity. More recently, they have appeared in some systems of physical interest, such as models for two-phase flow and a non-standard model for chromatography. The new examples, unlike the original one, all exhibit loss of hyperbolicity in regions of phase space, as well as the potential to allow these low-regularity waves. | ||
Wed 11/4
Counting Factors (Symbolic Dynamics Workgroup)
David Ralston
Start: 4:30 pm
Location: MA 240 (same as CH 240)
MA 240 (same as CH 240)
We will introduce the "block-growth function," which counts the number of
factors of different lengths which appear in an infinite word. The rate
at which this monotone function grows encodes much information about the
original word. We will investigate the minimal non-trivial block growth
rate, explicit examples of linear and other polynomial rates, and ask
questions about other possible growth rates.
"When the Problem Gets Tough, Change the Problem" (Radical Pi)
Bart Snapp
Start: 5:00 pm
Location: MA 052
MA 052
In this talk we will discuss a polynomial analogue of the (in)famous Collatz
Problem.
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Thu 11/5
Yongfeng Li (IMA)
Start: 2:30 pm
End: 3:30 pm
Location: EA 295
EA 295
In this talk, we will discuss the nonlinear oscillatory
chemical dynamics in a closed isothermal reaction system: a reversible Lotka-Volterra model. This is a 3D dissipative, singular perturbation of a conserved Lotka-Volterra model, with free energy serving as the global Lyapunov function. We will show that while the reaction eventually reaches the chemical equilibrium, quasi-stationary oscillations occurs as interesting intermediate dynamics. Moreover, there is a natural distinction between oscillatory and non-oscillatory regions in the phase space. Arc formulae and motivic rationality (Logic Seminar)
Hans Schoutens (NYC College of Technology, visiting OSU)
Start: 3:30 pm
End: 4:30 pm
Location: CC246
CC246
Using the schemic Grothendieck rings introduced in my earlier
talks, I will describe a new variant of motivic integration on a scheme of
finite type over an algebraically closed field via the notion of arc
formula(ry). In certain cases (linear singularities), this will lead to a
new, characteristic-free proof of the motivic rationality of the geometric
Igusa zeta series of a hypersurface, by means of a simple algorithm.
Wilhelm Schlag (University of Chicago)
Start: 4:30 pm
End: 5:30 pm
Location: CH 240 (MA 240)
CH 240 (MA 240)
I will give an overview of some of the solution theory of nonlinear wave equations
such as the wave map or Yang-Mills equations. Wave maps are wave-equations taking
their values in manifolds and are also known as nonlinear sigma models.
Even though many questions remain unanswered, we do have some understanding of how
the geometry of the target influences the long-time existence of the solutions (via
positive vs. negative curvature, and the existence of finite energy harmonic maps).
Special emphasis will be placed on the notion of energy critical equations.
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Fri 11/6
Geometry and Topology from Point Cloud Data (Geometry Topology and Data Analysis)
Tamal Dey (OSU (cse))
Start: 3:30 pm
End: 4:30 pm
Location: MW154
MW154
Abstract: Recent advances in laser technology have made it possible to
sample the boundary of a real world object to produce a large amount
points. Many applications require to reconstruct the object from this
point sample. We will describe algorithms for this reconstruction which
have topological and geometric guarantees. In the process I shall introduce
the various complexes that can be built from point cloud data which
help in deciphering geometry and topology of the hidden sampled object.
In a follow up lecture I shall describe an algorithm to decipher the
topology of a hidden manifold from point cloud data in high dimensions.
Characterizations of some classes of rings via Rickart modules (The OSU-OU Ring Theory Seminar)
Gangyong Lee (The Ohio State University)
Start: 4:45 pm
End: 5:45 pm
Location: MW 154
MW 154
Let $M$ be a right $R$-module and $S= End_R(M)$. $M_R$ is called
a \emph {Rickart module} if the right annihilator in $M$ of any single element of $S$ is generated by an idempotent in $S$. In this talk, we will discuss characterizations of classes of rings using the Rickart property of modules over them. In particular, the classes of right semihereditary rings, right hereditary rings, von Neumann regular rings, $V$-rings and semisimple artinian rings, will be characterized. We will show that a commutative domain $R$ is a Pr\"{u}fer domain iff the free module | ||
Sat 11/7
Workshop on Algebraic cycles (Event - )
End: 12:30 pm
Start: Nov 7 2009 - 8:30am
End: Nov 8 2009 - 12:30pm
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Sun 11/8
Workshop on Algebraic cycles (Event - )
End: 12:30 pm
Start: Nov 7 2009 - 8:30am
End: Nov 8 2009 - 12:30pm
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Mon 11/9
Link surgery, monopole Floer homology, and odd Khovanov homology (Topology Seminar)
Jonathan Bloom (Columbia University)
Start: 3:30 pm
Location: TBA
TBA
I'll describe new invariants of a framed link in a 3-manifold, which
arise as the pages of a spectral sequence generalizing the surgery
exact triangle in monopole Floer homology. The construction introduces
a connection between the topology of link surgeries and the
combinatorics of polytopes called graph associahedra. For a classical link L in S3, we obtain a sequence of bigraded vector spaces,
interpolating between the reduced, Z/2Z Khovanov homology of L and a
version of the monopole Floer homology of the branched double cover.
Periods and invariant functionals with respect to unitary groups (Number Theory Seminar)
Erez Lapid (Hebrew University)
Start: 4:30 pm
End: 5:30 pm
Location: MW 154
MW 154
Let E/F be a quadratic extension of number fields. Jacquet developed the relative trace formula to show that a cuspidal representation pi of GL_n(A_E) is distinguished by the quasi-split unitary group wrt E/F if and only if pi is Galois invariant. I will discuss the local analogue of this question: what can be said about the space of functionals invariant under a unitary group.
(Joint work with Brooke Feigon and Omer Offen.) Computation and Cell Biology (Invitation to Research)
Ching-Shan Chou (OSU)
Start: 4:30 pm
End: 5:30 pm
Location: CH 240
CH 240
Differential equations and numerical simulation have been widely used in modeling biological systems. In this talk, I will introduce two biological systems related to cell signaling:
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