Versality of Brill-Noether flags and degeneracy loci of twice-marked curves

Nathan Pflueger

A Brill-Noether degeneracy locus is closure in $\Pic^d(C)$ of the locus of line bundles with a specified rank function $r(a,b)=h^0(C,L(-ap-bq))$. These loci generalize the classi…