THE COVARIANT SCATTERING AND COHOMOLOGY OF W(3) STRINGS

A general formalism for covariant W3 string scattering is given. It is found necessary to use screening charges that are constructed from th e W3 fields including ghosts. The scattering amplitudes so constructed contain within them Ising model correlation functions and agree with those found previously by the authors. Using the screening charge and a picture-changing operator, an infinite number of states in the cohom ology of Q are generated from only three states. We conjecture that, a part from discrete states, these are all the states in the cohomology of Q.