On Lagrangian fibrations by Jacobians, II
Abstract
Let Y → ℙn be a flat family of reduced Gorenstein curves, such that the compactified relative Jacobian is a Lagrangian fibration. We prove that X is a Beauville–Mukai integrable system if n = 3, 4, or 5, and the curves are irreducible and non-hyperelliptic. We also prove that X is a Beauville–Mukai system if n = 3, d is odd, and the curves are canonically positive 2-connected hyperelliptic curves.