Date/Time: 14 October 2022, 4:30pm ET
 Location: Millersville University, Wickersham Hall, Room 104
     Zoom: https://millersville.zoom.us/j/98919210979
                  (contact any of the organizers if you need the Zoom
                  Meeting ID or passcode)
  Speaker: Hannah Schwartz, Princeton University
    Title: Homotopy 4-spheres from a 5D perspective

 Abstract: The smooth, generalized Poincaré conjecture -- that
all smooth homotopy spheres are diffeomorphic to the standard one --
remains unknown only in dimension four. In this talk, we will examine
doubles of homotopy 4-spheres (also homotopy 4-spheres) by viewing these
4-manifolds as boundaries of 5-manifolds. Passing to a 5-dimensional
perspective in this context is both practical and useful, since many
handlebody calculus issues from dimension four can be avoided with an
extra dimension. To convince you of this, I will sketch the proof of an
(in-progress) result joint with Naylor and Gabai that certain Gluck
twists are standard: in short, because they bound a 5-ball!