Classical W-algebras and generalized Drinfeld-Sokolov bi-Hamiltonian   systems within the theory of Poisson vertex algebras
  We provide a description of the Drinfeld-Sokolov Hamiltonian reduction for the construction of classical W-algebras within the framework of Poisson vertex algebras. In this context, the gauge group action on the phase space is translated in terms of (the exponential of) a Lie conformal algebra action on the space of functions. Following the ideas of Drinfeld and Sokolov, we then establish under certain sufficient conditions the applicability of the Lenard-Magri scheme of integrability and the existence of the corresponding integrable hierarchy of bi-Hamiltonian equations. 
Alberto De Sole, Victor G. Kac and Daniele Valeri
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