A funny encounter with immersions of spheres

  • Venue:

    2.058

  • Date:

    05.11.2020

  • Speaker:

    Tam Nguyen Phan

  • Time:

    16:00 – 17:30

  • It is a common topology homework exercise to prove that any embedding of a closed, orientable n-manifold M, such as the n-sphere, into R^{n+1}, is separating (i.e. has disconnected complement). However, this homework problem has never been posed with “embedding”
    replaced by “immersion”, probably because it seems at first glance to complicate the problem for no good reason. But there is actually an interesting reason. This talk is based on joint work with Michael Freedman.