All talks are held on Friday in 381-T, starting at **3:30 pm**, unless otherwise noted.

** Friday, April 18th, 2014**

**Speaker**: Tian Yang

**Title**: Hyperbolic cone metrics on 3-manifolds with boundary

** Friday, April 25th, 2014 **

** Speaker** Tian Yang

** Title ** A deformation of Penner's simplicial coordinate

** Friday, May 2, 2014 **

** TBA**

** Friday, Jan. 18, 2013 **

**Speaker** Kenji Kozai

**Title**: Singular hyperbolic structures from Sol.

** Friday, Jan. 25, 2013 **

**Speaker** Martin Bridgeman

**Title**: The Pressure metric for convex Anosov representations

**Abstract** Using the thermodynamics formalism,
we introduce a notion of intersection for convex Anosov representations. We
also produce a Out-invariant Riemannian metric on the smooth points of the
deformation space of convex, irreducible representations of a word
hyperbolic group G into SL(m,R) whose Zariski closure contains a
generic element. In particular, we produce a mapping class group
invariant Riemannian metric on Hitchin components which restricts to
the Weilâ€“Petersson metric on the Fuchsian locus.

** Friday, Feb. 1, 2013 **

**Speaker** Ara Basmajian

**Title**: Lengths of closed geodesics and their intersection numbers on a hyperbolic surface

**Abstract**
We'll discuss in various contexts the relationship between the lengths of closed geodesics and their number of intersections on a hyperbolic surface.

** Friday, Feb. 8, 2013 **

**Speaker** Zhiren Wang

**Title** Global rigidity of abelian Anosov actions on tori

**Abstract**
As part of a more general conjecture, the following statement was expected to hold: if a smooth $\mathbb Z^r$-action $\alpha$ on a torus contains one Anosov element and has no rank-1 factor, then it must be smoothly conjugate to its linearization $\alpha_0$, which is an action by toral automorphisms. Fisher, Kalinin and Spatzier showed this holds under the assumption that $\alpha$ has at least one Anosov element in every Weyl chamber of the linearization action. We will verify that this assumption is redundant, hence fully establish the statement above. This is a joint work with Federico Rodriguez Hertz.

** Friday, Feb. 15, 2013 **

**Speaker** Amie Wilkinson

**Title**: Absolute continuity, exponents, and rigidity.

**Abstract** The geodesics in a compact surface of negative curvature
display stability properties originating in the chaotic, hyperbolic
nature of the geodesic flow on the associated unit tangent bundle.
Considered as a foliation of this bundle, this collection of geodesics
persists in a strong way when one perturbs of the Riemannian metric,
or the geodesic flow generated by this metric, or even the time-one
map of this flow: for any perturbed system there is a corresponding
"shadow foliation" with one-dimensional smooth leaves that is
homeomorphic to the original geodesic foliation. A counterpart to
this foliation stability is a curious rigidity phenomenon that arises
when one studies the disintegration of volume along the leaves of this
perturbed shadow foliation. I will describe this phenomenon and its
underlying causes. This is work with Artur Avila and Marcelo
Viana.

** Friday, Feb. 22, 2013 **

**Speaker** No Seminar

** Friday, March 1, 2013 **

**Speaker** John Pardon

**Title**: Obstruction bundles and counting holomorphic disks in Heegaard Floer homology

**Abstract**: I will discuss an approach to count the holomorphic disks which
give the boundary operator in Heegaard Floer homology. However, no
previous knowledge of Heegaard Floer homology is necessary to understand
the talk. I'll discuss how to rephrase the problem of counting
holomorphic disks in a certain high dimensional symplectic manifold as a
lower dimensional enumerative problem. To approach this problem, we
consider a Hurwitz space of ramified covers of a "domain" on a Riemann
surface $\Sigma_g$ and ask to count the covers $S\to\Sigma_g$ where $S$
admits a holomorphic map to the unit disk. It turns out that in some
cases, this number is equal to a certain relative Euler class of an
"obstruction bundle" over the Hurwitz space, whereas in others, there are
parts of the boundary that we don't yet understand how to deal with.

** Friday, March 8, 2013 **

**Speaker** Harry Baik

**Title**: Groups acting on the circle with dense invariant laminations

**Abstract**: I propose a new way to look at the group actions on the
circle via the number of transverse dense invariant laminations. As a
motivational example, we characterize the Fuchsian groups in terms of
the invariant laminations. Having infinitely many invariant
laminations with some additional assumptions on the laminations
guarantees that the given group is Fuchsian. From the ideas developed
in the proof, we can also prove that having three invariant
laminations with stronger assumptions gives the same result. The key
ingredient is the convergence group theorem. The development of the
theory was motivated by Thurston's universal circle construction for
tautly foliated 3-manifold groups.

** Friday, October 5, 2012 **

**Speaker**: Yitwah Cheung (SFU)

**Title**: Generalized Gauss measures and Levy's constant

** Friday, October 12, 2012 **

**No Seminar**

** Friday, October 19, 2012 **

**Speaker**: Ronen Mukamel (Stanford)

**Title**:Trace fields and Veech groups without parabolics

** Friday, October 26, 2012 **

**No Seminar**

** Friday, November 2, 2012 **

**Speaker**: No Seminar

** Friday, November 9, 2012 **

**Speaker**:Rafe Mazzeo

** Friday, November 16, 2012 **

**Speaker**: Jayadev Athreya

**Title**: Gap Distributions and Homogeneous Dynamics
\

** Friday, November 23, 2012 **

**No Seminar**

** Friday, November 30, 2012 **

**Speaker** Alex Wright

**Title**: SL(2,R) orbit closures of translation surfaces.

** Friday, January 13th, 2012 **

**Speaker**: Ronen Mukamel (Stanford)

**Title**: Lattice Veech groups in SL(2,O_D), Part I

** Friday, January 20th, 2012 **

**Speaker**: Ronen Mukamel (Stanford)

**Title**: Lattice Veech groups in SL(2,O_D), Part II

** Friday, January 27th, 2012 **

**Speaker**: Kenji Kozai (Stanford)

**Title**: Ideal triangulations of pseudo-Anosov mapping tori

** Friday, February 3rd, 2012 **

**Speaker**: Yitwah Cheung (San Francisco State)

**Title**: Bounded geodesics are winning (with Jon Chaika and Howard Masur)

** Friday, February 10th, 2012 **

**Speaker**: Dimitri Zvonkine (Stanford)

**Title**: The psi-classes on the space of stable maps, I

** Friday, February 17th, 2012 **

**Speaker**: Dimitri Zvonkine (Stanford)

**Title**: The psi-classes on the space of stable maps, II

** Friday, February 24th, 2012 **

**Speaker**: John Pardon (Stanford)

**Title**: Volumes of moduli spaces of flat bundles over a Riemann
surface

** Friday, March 2nd, 2012 **

**Speaker**: Jenya Sapir (Stanford)

**Title**: Hausdorff dimension of sets of curves on surfaces

** Friday, March 9th, 2012 **

**Speaker**: No Seminar this week

** Friday, March 16th, 2012 **

**Speaker**: Curt McMullen (Harvard)

**Title**: Cascades in the dynamics of surface foliations

** Friday, March 23rd, 2012 **

No Seminar

** Friday, April 6th, 2012: **

** Friday, April 13th, 2012: **

** Speaker**: Tom Church (Stanford)

**Title**: A conjecture on stability in the unstable cohomology of moduli space

** Friday, April 20th, 2012: **

** Speaker:** Guillaume Dreyer (USC)

**Title**: Geometric properties of Anosov representations

** Friday, April 27th, 2012: **

**Speaker**: Tan Ser Peow (Singapore)

**Title**: A dilogarithm identity on moduli spaces of curves

** Friday, May 4th, 2012: **

**Speaker**: Kasra Rafi (Oklahoma)

**Title**: The Teichmuller space is semi-hyperbolic

** Friday, May 11th, 2012: **

**Speaker**: Thomas Koberda (Harvard)

**Title**: Generalizations of the Nielsen--Schreier Theorem

** Friday, May 18th, 2012: **

** No Seminar**

** Friday, May 25th, 2012: **

**Speaker**: Shinpei Baba (Caltech)

**Title**: Grafting Complex Projective Structures

** Friday, June 15st, 2012: **

**Speaker**: Scott Wolpert

**Title**: Infinitesimal deformations of nodal stable curves

Last modified: Sat Jan 07 09:30:09 PST 2012