Algebraic Geometry Seminar: "A Lagrangian sphere which is not a vanishing cycle"

Abstract: Let X be a smooth projective variety with its induced Kahler structure.  If X admits a degeneration to a nodal variety, then X contains a Lagrangian sphere as the vanishing cycle.  Donaldson asked whether the converse holds.  We answer this question in the negative for Calabi-Yau threefolds.

Host: Matt Kerr