Lagrangian and Hamiltonian structures for the constant astigmatism equation (Q2866168)

The authors find a Lagrangian representation and the corresponding Hamiltonian representation for the constant astigmatism equation. Using these representations and extra conservation law densities, they construct a first evolution commuting flow of third order. They also apply the recursion operator and present a second Hamiltonian structure. For the obtained bi-Hamiltonian structure this allows to replicate infinitely many local commuting flows and corresponding local conservation law densities.