In this paper we show that the classical results on the existence and
uniqueness of moment maps in symplectic geometry generalize directly to weak
homotopy moment maps in multisym- plectic geometry. In particular, we show that
their existence and uniqueness is governed by a Lie algebra cohomology complex
which reduces to the Chevalley-Eilenberg complex in the symplectic setupComment: Incorporated the referee's suggestions and fixed some typos. To
appear in Journal of Geometry and Physic