Quantization of the Drinfeld-Sokolov reduction

Abstract We show that the quantum Drinfeld-Sokolov reduction of the affine Kac-Moody algebra sl( n ) Λ gives the W n -algebra of Fateev-Zamolodchikov-Lukyanov. We derive this W n -algebra explicitly as a BRST cohomology algebra, using the homological technique of spectral sequences.