Exact solutions in multidimensional cosmology with a term

A cosmological model describing the evolution of $n$ Einstein spaces $(n>1)$ in the theory with the cosmological constant $\Lambda\ne0$ is considered. In the case, when all spaces are Ricci–flat, the exact solutions of the Einstein and Wheeler–DeWitt equations are obtained. For $\Lambda<0$ the solutions are found that are treated as quantum wormholes. A generalization of the solutions to the case of a massless scalar field is obtained.