Pullbacks of hyperplane sections for Lagrangian fibrations are primitive
  Let p: M -> B be a Lagrangian fibration on a hyperkahler manifold of maximal holonomy (also known as IHS), and H the generator of the Picard group of B. We prove that the pullback $p^*(H)$ is a primitive class on M. 
Ljudmila Kamenova, Misha Verbitsky
math.AG