Metro Area Differential Geometry Seminar




Directions & Local

Past Meetings


The following speakers are confirmed:

  • Sun-Yung Alice Chang (Princeton)
  • Title: Moser-Onofri inequality and the sigma_2 functional.
    Abstract: T. Branson has a famous remark viewing the Moser-Onofri inequality on the 2-sphere as the limiting case of the Sobolov embedding inequality on a d-dimensional sphere as d tends to 2. In the first part of the talk I will present a proof that makes this remark rigorous. In the second part of the talk I will discuss the analogue of the functional on the sigma_2 curvature on 4-manifolds, following the recent work of Gursky-Streets, I will discuss the sharp inequality of the functional on the 4-sphere and the scheme to achieve the minimum for the functional on a class of metrics on 4-manifolds.

  • Jake Solomon (Hebrew)
  • Title: Point-like bounding chains in open Gromov-Witten theory.
    Abstract: Over a decade ago, Welschinger defined real enumerative invariants in dimensions 2 and 3. It has remained an open problem to extend these invariants to higher dimensions. I will discuss a solution to this problem in the language of open Gromov-Witten theory. The key idea is that boundary point constraints should be replaced with canonical gauge equivalence classes of Maurer-Cartan elements (bounding chains) in the relevant Fukaya A-infinity algebra. The resulting invariants satisfy an open WDVV equation. All invariants for projective spaces have been calculated. In connection with open WDVV, a relative version of the quantum product appears. Real structures do not play an essential role in our arguments. This is joint work with S. Tukachinsky.

  • Steve Zelditch (Northwestern)
  • Title: Local and Global Harmonic Analysis.
    Abstract: Harmonic analysis is about eigenfunctions of the Laplacian on Riemannian manifolds. It begins with Fourier analysis on Euclidean space or tori and proceeds to other metrics and manifolds. Local Harmonic analysis is about the analysis of eigenfunctions on `small balls' of radius equal to a few hundred wavelengths. Global Harmonic analysis uses the wave equation and geodesic flow. A well-known case is quantum chaos, which studies the effect of ergodicity of the geodesic flow on the structure of eigenfunctions. This talk is about recent results on nodal sets of eigenfunctions obtained by both local and global methods.

    Past Speakers

    Updated Fall 2016 -- Department of Mathematics, Johns Hopkins University. Please contact Jacob Bernstein about errors on this site.