Hello everyone,
This week we are really excited to have Roman Aranda (virtually) coming down from Iowa to speak.
His title and abstract are below:
4-manifolds with small trisection genus Speaker: Roman Aranda, University of Iowa Time: Oct 28, 2020, 3:45 PM Room: Virtual meeting https://meet.google.com/frv-bgow-byi
Abstract: In 2016, D. Gay and R. Kirby proved that every closed 4-manifold can be decomposed as the union of three 4-dimensional simple pieces with triple intersection a closed orientable surface of genus g. This decomposition is called a trisection of genus g for M. In 2018, M. Chu and S. Tillmann gave a lower bound for the trisection genus of a closed 4-manifold in terms of the rank of its fundamental group. In this talk, we show that given a group G, there exists a 4-manifold M with fundamental group G with trisection genus achieving Chu-Tillmann’s lower bound. The proof uses techniques of knot theory in simple 3-manifolds.
___________________ Neil Hoffman