A codimension 2 component of the Gieseker-Petri locus
arXiv:2002.10550
Abstract
We show that the Brill-Noether locus M^3_{18,16} is an irreducible component of the Gieseker-Petri locus in genus 18 having codimension 2 in the moduli space of curves. This result disproves a conjecture predicting that the Gieseker-Petri locus is always divisorial.
arXiv commentFinal version, to appear in Journal of Algebraic Geometry