Abstracts
Speaker:
Jozef Przytycki (George Washington
University)
Title:
Skein Modules of
3-manifolds in historical perspective
Abstract:
I will describe theory of skein modules starting from its prehistory:
January 1987 visit of Jim Hoste to Vancouver. Then I will outline
results we obtained in five years of our fruitful collaboration,
including computation of the Kauffman bracket skein module of lens
spaces and
Whitehead manifolds.
I will sketch recent grow of theory stressing its successes and
potentials, concentrating on developments I observed first hand.
I will end with few open problems some of which I am studying now with
my students.
Speaker:
Daniel Ruberman (Brandeis University)
Title:
Stabilization in 4-dimensional topology
Abstract:
The world of smooth 4-manifolds contains many exotic objects: manifolds
that are homeomorphic but not diffeomorphic, surfaces that are
smoothly knotted but topologically unknotted, diffeomorphisms that are
topologically but not smoothly isotopic. It is known that this exotic
behavior disappears after repeated stabilizations: connected sums with
standard manifolds such as the complex projective plane or a product of
spheres. I will talk about some examples where a single stabilization
suffices to cancel such exotic behavior, and prove a general “one
is enough” result for embedded surfaces.
This is joint work with Dave Auckly, Hee Jung Kim, Paul Melvin, and
Hannah Schwartz.
Speaker:
Scott Carter (University of South Alabama)
Title:
Braidings, Handle
decompositions, and Branched coverings
Abstract:
This tak is based upon past and on-going work with Seiichi Kamada.
Kamada's concept of a braid chart is a fundamental idea that can be
used to study branched coverings, braidings, and immersions and
embeddings of manifolds of dimension one through four. The chart is a
labeled oriented graph in the plane that has three types of vertices. A
sequence of charts in which successive charts differ from each other by
a move selected from a relatively small list can be used to describe a
braiding of a 3-dimensional manifold. This braiding is immersed in
codimension 2. The charts are assembled into a structure that we call a
curtain and that generalizes the Seifert surface. The curtain structure
can be used to describe representations of the fundamental group via a
handle description of the complement.
My goal in the talk will be to give several intricate examples of these
phenomena.
Speaker:
Sam Nelson (Claremont McKenna College)
Title:
Quandles and Knots
Abstract:
Quandles are algebraic structures whose axioms encode the Reidemeister
moves analogously to how the group axioms encode symmetry. In this talk
we will see some examples and history of quandles, culminating in Jim's
recent work.
Speaker:
Patrick Shanahan (Loyola Marymount)
Title:
Epimorphism of 2-bridge knots
Abstract:
In this talk I will discuss results from an ongoing collaboration with
Jim Hoste that began following a colloquium talk I gave at Pomona
College in 1997. Our initial investigation into the computation of
A-polynomials led to us to a more general study of epimorphisms of
2-bridge knot groups. I will discuss several results associated to
these epimorphisms that illustrate the beautiful correspondence that
exists between 4-plats, continued fractions, boundary slopes, and
algebraic invariants of 2-bridge knots. Central to this study is the
construction of a branched fold map between 2-bridge knot complements
that was introduced by Ohtsuki, Riley, and Sakuma. This work also
involves important contributions by undergraduate students Scott
Garrabrant (Pitzer College 2011) and Joshua Ocana-Mercado (Loyola
Marymount University 2018).