Interacting Theory of Collective and Topological Fields in 2 Dimensions

We propose a generalization of the collective field theory hamiltonian, including interactions between the original bosonic collective field $w_0 (z)$ and supplementary fields ${\bar w}_j (z)$ realizing classically a $w_\infty$ algebra. The latter are then shown to represent a 3--dimensional topological field theory. This generalization follows from a conjectured representation of the $W_{1 + \infty}$ algebra of bilinear fermion operators underlying the original matrix model. It provides an improved bosonization scheme for $1+1$ dimensional fermion theories.