Department of Mathematics

Please join the Department of Mathematics for the Brown/MIT Joint Geometric Analysis Seminar on April 13, 2026.

Register to Participate

  • Registration/Check in will be in the Kassar House Common Room, 151 Thayer Street
  • Talks will be in MacMillan Hall, Room 115, 167 Thayer Street

View the poster for full seminar schedule details.

Chao Li

Chao Li
Courant Institute (NYC)

3:00-4:00pm, MacMillan Hall 115

Immersions of small normal curvature

Given a closed manifold and a sufficiently large integer N, we study the smallest possible normal curvature, C_N(X), of all immersions of X into the unit ball of the N dimensional Euclidean space. This question was recently initiated by Gromov, who studied the case when X is the n-dimensional torus via Hilbert’s rational spherical design.
In this talk, we will discuss small-curvature immersions of products of spheres via minimal Veronese mappings, and prove the optimality of such immersions in some cases via intrinsic comparison geometry.

Antoine Song

Antoine Song
California Institute of Technology

4:30-5:30pm, MacMillan Hall 115

Harmonic maps into high-dimensional spheres

I will survey recent developments related to harmonic maps from surfaces to Euclidean spheres. Given a closed Riemann surface and a unitary representation of its fundamental group, classicalvariational theory produces a corresponding equivariant harmonic map from the Poincaré disk to a Euclidean sphere. In general not much can be said about the geometry of such maps. However, I will explain that by leveraging the theory of random matrices, if the representation is sufficiently generic, then the corresponding harmonic map becomes very close to an immersed hyperbolic plane inside a sphere. Moreover, the asymptotic limit is essentially unique. As one application, Ancona & Labourie & Roig Sanchis & Toulisse found a strong solution to a problem of S.T. Yau’s 1982 list about the existence of negatively curved minimal surfaces in spheres.

Partly joint with Riccardo Caniato and Xingzhe Li.