[Binghamton Geometry Topology Seminar] NEW TIME coffee and SAME TIME talk tomorrow

[sapir at math.binghamton.edu]

Hi everyone,

Due to the speaker's schedule, seminar coffee will
be from 1 to 2pm tomorrow. The links are as usual, but
details are below!

Best,
Jenya Sapir

---------------------------------------------------------------

This week our speaker is Rylee Lyman of Rutgers University. Links and
details are below.

Zoom link for the seminar, 2:50 - 3:50:
https://binghamton.zoom.us/j/94057178271

Zoom link for the
coffee, 1:00pm - 2:00pm:
https://binghamton.zoom.us/j/96674397432

Title:Â  Nielsen
realization for infinite-type surfaces

Abstract: We learn the
classification of surfaces early in our
mathematical careers: the
homeomorphism type of an orientable surface
with finitely generated
fundamental group is determined by genus,
punctures and boundary
components. Without the finite generation
assumption, there is still
a classification, due to Kerékjártó and
Richards. These surfaces are of infinite type. Associated to any
surface is its mapping class group. A famous theorem of Kerckhoff
from
1983 solves the "Nielsen realization" problem posed in
1932: finite
subgroups of the mapping class group of a finite-type
surface of
negative Euler characteristic are exactly the groups of
isometries of
some hyperbolic metric on the surface. Recently, joint
with Santana
Afton, Danny Calegari and Lvzhou Chen, I extended
Kerckhoff's theorem to
orientable, infinite-type surfaces. I'd like
to introduce infinite-type
surfaces and discuss the theorem and some
of its consequences.
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