The only way this can happen is if space has four-or-more-dimensional “handles” or “holes” (like a coffee mug or a donut). hmmmmm... You can derive an expanding finite accelerating spherical k=-1 model from the physics that I previously mentioned: http://www.lns.cornell.edu/spr/2006-02/msg0073320.html Correct me if I am wrong, but in this case, the field equations of general relativity can be satisfied with vacuum energy density proportional to the cosmological constant.