Speaker: Benjamin Church (Stanford University)

Title: Curves on complete intersections and measures of irrationality

Abstract:

Given a projective variety $X$, it is always covered by curves obtained by taking the intersection with a linear subspace. We study whether there exist curves on $X$ that have smaller numerical invariants than those of the linear slices. If $X$ is a general complete intersection of large degrees, we show that there are no curves on $X$ of smaller degree, nor are there curves of asymptotically smaller gonality. This verifies a folklore conjecture on the degrees of subvarieties of complete intersections as well as a conjecture of Bastianelli--De Poi--Ein--Lazarsfeld--Ullery on measures of irrationality for complete intersections. This is joint work with Nathan Chen and Junyan Zhao.