Speaker | Time | Room | Title |
Benson Farb, U Chicago | 10:30-11:30 am | 151 Sloan | Problems and progress in understanding the Torelli group |
Ko Honda, USC | 1:30-2:30 pm | 151 Sloan | Reeb vector fields and open book decompositions |
Henry Segerman, Stanford | 2:45-3:45 pm | 151 Sloan | Incompressible Surfaces in Punctured Torus Bundles, and the Ideal Points They Come From |
Amie Wilkinson, Northwestern | 4-5 pm | 151 Sloan | Asymmetrical diffeomorphisms |
Benson Farb. Title: Problems and progress in understanding the
Torelli group
Abstract:
The Torelli group T(S) of a surface S is defined to be the subgroup of the
mapping class group of S consisting of the elements acting trivially
on H1(S,Z). The study of T(S) connects to 3-manifold
theory, symplectic representation theory, combinatorial group theory,
and algebraic geometry. In this talk I will explain some of the main
themes in this beautiful topic. I will describe some recent progress in
this area, as well as some of the basic open problems.
Ko Honda. Title: Reeb vector fields and open book decompositions
Abstract:
According to a theorem of Giroux, there is a 1-1 correspondence between
isotopy classes of contact structures and equivalence classes of open book
decompositions. We give partial results towards calculating the contact
homology of a contact structure (M,&xi) (in dimension 3) which is supported
by an open book with pseudo-Anosov monodromy. This is joint work with
Vincent Colin.
Henry Segerman. Title: Incompressible Surfaces in Punctured Torus Bundles, and the Ideal Points
They Come From
Abstract:
Culler and Shalen give us a way to produce incompressible surfaces in a
3-manifold from ideal points of its character variety. However, not much
is known about the reverse direction: given an incompressible surface,
does it come from an ideal point? I will talk about this question in the
context of punctured torus bundles, for which the answer is always "Yes".
Amie Wilkinson. Title: Asymmetrical diffeomorphisms
Abstract:
Abstract: Which diffeomorphisms of a compact manifold M commute with no
other diffeomorphisms (except their own powers)? Smale asked if such
highly asymmetrical diffeomorphisms are typical, in that they are dense in
the Cr topology on the space of Cr diffeomorphisms
Diffr(M). In this
talk I will explain the recent (positive) solution to Smale's question for
C1 symplectomorphisms and volume-preserving diffeomorphisms. I will also
discuss progress on the general case. This is joint work with Christian
Bonatti and Sylvain Crovisier.
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