We summarize some recent results obtained in collaboration with J. McCarthy on the spectrum of physical states in W 3 gravity coupled to c = 2 matter. We show that the space of physical states, defined as a semi-infinite (or BRST) cohomology of the W 3 algebra, carries the structure of a BV-algebra. This BV-algebra has a quotient which is isomorphic to the BV-algebra of polyvector fields on the base affine space of SL(3, C). Details will appear elsewhere.Throughout this paper we will use the notation h for the Cartan subalgebra, h * Z for the set of integral weights, P + for the set of dominant integral weights, P ++ for the set of strictly dominant integral weights, ∆ + for the positive roots and W for the Weyl group of some Lie algebra g. L(Λ) will denote the finite dimensional irreducible representation of g with highest weight Λ ∈ P + and ℓ(w) the length of w ∈ W . In the following g will always refer to sl 3 .
The W 3 algebra and its modulesThe W 3 algebra with central charge c ∈ C (denoted simply by W in the sequel) is defined as the quotient of the free Lie algebra generated by L m , W m , m ∈ Z, by the ideal generated by the following commutation