  A Brill-Noether locus is a subscheme of the moduli of bundles E over a curve
C defined by requiring E to have a given number of sections, or homomorphisms
from another bundle. There are a number of different types, that can be treated
by determinantal methods, with symmetry or skewsymmetry arising from Serre
duality. They have many beautiful applications to curves, K3 surfaces and Fano
3-folds.
