Boris Dubrovin - "On deformations of integrable hierarchies".

We will address the problem of classification of hierarchies of systems of bihamiltonian PDEs 
with one spatial dimension. Under certain nondegeneracy assumptions the complete set of invariants 
of the underlying bihamiltonian structures will be constructed. These invariants will be computed 
for the examples of Drinfeld - Sokolov integrable hierarchies associated with an arbitrary simple Lie algebra.