Интегрируемые бездисперсионные уравнения типа Хироты и гиперповерхности в лагранжевом грассманиане

Equations of the dispersionless Hirota type typically arise in the tau-function representation of dispersionless multi-diemnsional hierarchies.
I will discuss an intrinsic approach to equations of this class, revealing a remarkable correspondence of the problem with hypersurfaces of the Lagrangian Grassmannian.