  We study a general credence goods model with N problem types and N
treatments. Communication between the expert seller and the client is modeled
as cheap talk. We find that the expert's equilibrium payoffs admit a geometric
characterization, described by the quasiconcave envelope of his belief-based
profits function under discriminatory pricing. We establish the existence of
client-worst equilibria, apply the geometric characterization to previous
research on credence goods, and provide a necessary and sufficient condition
for when communication benefits the expert. For the binary case, we solve for
all equilibria and characterize client's possible welfare among all equilibria.
