Department of Mathematics,
University of California San Diego
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Math 208: Seminar in Algebraic Geometry
Dr. Eric Jovinelly
Brown University
Free Curves in Singular Varieties
Abstract:
Rational curves are intricately linked to the birational geometry of varieties containing them. Certain curves, called free curves, have the nicest deformation properties. However, it is unknown whether mildly singular Fano varieties contain free rational curves in their smooth locus. In this talk, we discuss free curves of higher genus. Using recent results about tangent bundles, we prove that any klt Fano variety has higher genus free curves. We then use the existence of such free curves to get some applications: we prove the existence of free rational curves in terminal Fano threefolds; obtain an optimal upper bound on the length of extremal rays in the Kleiman-Mori cone of any klt pair; and study the fundamental group of the smooth locus of a Fano variety. This is joint work with Brian Lehmann and Eric Riedl.
Host: James McKernan
November 17, 2025
4:00 PM
APM 7218
Research Areas
Algebraic Geometry****************************