Split String Formalism and the Closed String Vacuum, II
  In this paper we consider a class of generalizations of Schnabl's solution of open bosonic string field theory obtained by replacing the wedge state by an arbitrary combination of wedge states. We find that under a few modest conditions such generalizations give a sensible deformation of Schnabl's solution for the closed string vacuum--in particular, we can compute their energies and show that they reproduce the value predicted by Sen's conjecture. Though these solutions are apparently gauge equivalent, they are not in general related by midpoint-preserving reparameterizations. 
Theodore Erler