School of Mathematics

We will discuss a proof that the integral Hodge conjecture is false for a very general abelian variety of dimension ≥ 4. Associated to any regular matroid is a degeneration of principally polarized abelian varieties. We introduce a new combinatorial...

We revisit the question of whether it is possible to build succinct non-interactive arguments (SNARGs) for all of NP under standard cryptographic assumptions. In particular, we give a candidate non-adaptive SNARG for NP and prove its soundness under...

A result of Simpson characterizes subspaces that are (irreducible) algebraic varieties on both sides of the rank one Riemann-Hilbert correspondence. This result suggests an underlying Ax-Schanuel statement. In joint work with Jacob Tsimerman we...

We prove that in any dimension n there exists an origin-symmetric ellipsoid of volume c n^2 that contains no points of Z^n other than the origin. Here c > 0 is a universal constant. Equivalently, there exists a lattice sphere packing in R^n whose...

In this talk, I will discuss the barcode entropy—the exponential growth rate of the number of not-too-short bars—of the persistence module associated with the relative symplectic cohomology SHM(K) of a Liouville domain K embedded in a symplectic...

In this talk, I will present joint work with Charles Bordenave and Mostafa Sabri establishing quantum ergodicity and quantum weak mixing for sequences of finite Schreier graphs converging, in the Benjamini–Schramm sense, to an infinite Cayley graph...

The regularity lemma says that every discrete object can be partitioned into a small number of random-like subobjects. But how small is small? And can we make small smaller if we assume that our given object is simple? And what does it mean for a...

Essentially optimal estimates have been obtained for mean values of Vinogradov’s exponential sum as a consequence of the decoupling method (by Bourgain, Demeter and Guth), and the efficient congruencing method (by the speaker). Such work makes...

The very first result ever proved about tournaments is due to Rédei, who nearly 100 years ago proved that every tournament contains a Hamiltonian directed path. Since then, questions and results about directed paths in tournaments have become a...

In this talk I will introduce the idea of Floer homotopy theory and show how it can be used to give lower bounds on degenerate Lagrangian intersections, in the case of plumbings of cotangent bundles along a submanifold. The strength of the invariant...