Product formulas on a unitary group in three variables

We obtain some basic partial differential operators connected with nonholomorphic automorphic forms on $\Gamma \backslash U(2, 1)/K$. We give the corresponding Eisenstein series of weight $k$ and automorphic Green functions of weight $k$. Moreover, we get the product formulas connected with them. As a consequence of the product formulas, we give the functional equations of Eisenstein series associated to a convex cocompact subgroup of U(2,1).