Previous Conferences & Workshops

Oct
17
2011

Computer Science/Discrete Mathematics Seminar I

On the Number of Hamilton Cycles in Psdueo-Random Graphs
Michael Krivelevich
11:15am|S-101

A pseudo-random graph is a graph G resembling a typical random graph of the same edge density. Pseudo-random graphs are expected naturally to share many properties of their random counterparts. In particular, many of their enumerative properties...

Oct
14
2011

Workshop on Symplectic Dynamics

Entropy zero symplectic diffeomorphisms of S2
John Franks
11:30am|Wolfensohn Hall
This talk will discuss joint work with Michael Handel concerning the dynamic structure of symplectic diffeomorphisms of the two-sphere. The intended application is the study of groups of "fully supported" diffeomorphisms (e.g. analytic) and the...
Oct
14
2011

Workshop on Symplectic Dynamics

New contact Anosov flows via Foulon surgery
Boris Hasselblatt
10:15am|Wolfensohn Hall
Geodesic flows of Riemannian or Finsler manifolds have been the only known contact Anosov flows. We show that even in dimension 3 the world of contact Anosov flow is vastly larger via a surgery construction near a transverse Legendrian knot that...
Oct
14
2011

Workshop on Symplectic Dynamics

Generic existence of an elliptic closed geodesic in the 2-sphere
Gonzalo Contreras
9:00am|Wolfensohn Hall

We prove that there is an open and dense set in the C2 topology of riemannian metrics on the 2-sphere whose geodesic flow has an elliptic closed geodesic.

This result recovers, in a generic sense, a theorem by H. Poincaré 1904 and proves a conjecture...

Oct
13
2011

Joint IAS/Princeton University Number Theory Seminar

On Real Zeros of Holomorphic Hecke Cusp Forms and Sieving Short Intervals
Kaisa Matomäki
4:30pm|S-101

A. Ghosh and P. Sarnak have recently initiated the study of so-called real zeros of holomorphic Hecke cusp forms, that is zeros on certain geodesic segments on which the cusp form (or a multiple of it) takes real values. In the talk I'll first...

Oct
13
2011

Workshop on Symplectic Dynamics

K3 and the planar 4 body problem
Richard Montgomery
4:30pm|Wolfensohn Hall
Newton's differential equations for the N-body problem have rotational and translational symmetry. Their flow is incomplete due to collisions. Symplectic reduction eliminates the symmetries. Levi-Civita regularization eliminates the binary collision...
Oct
13
2011

Workshop on Symplectic Dynamics

Essential coexistence of zero and nonzero Lyapunov exponents for volume preserving maps and flows
Yakov Pesin
2:30pm|Wolfensohn Hall

I will describe an example of a $C^\infty$ volume preserving topologically transitive diffeomorphism of a compact smooth Riemannian manifold which is ergodic (indeed is Bernoulli) on an open and dense subset $U$ of not full measure and has zero...

Oct
13
2011

Workshop on Symplectic Dynamics

Flows with nested invariant sets
Krystyna Kuperberg
11:30am|Wolfensohn Hall

Let $\phi : \mathbb R\times X\to X$ be a dynamical system, an $\mathbb R$-action, defined on the metric space $X$. A nonempty, closed invariant set is minimal if it contains no proper, nonempty, closed invariant subset. We will show a construction...

Oct
13
2011

Workshop on Symplectic Dynamics

Global surfaces of section of tight Reeb flows and applications
Umberto Hryniewicz
10:15am|Wolfensohn Hall
In this talk we study the existence question of disk-like global surfaces of section of tight Reeb flows on the 3-sphere and on lens spaces, and describe some applications. For instance, we find new global sections on strictly convex 3-dimensional...