Open and Closed Universes in Brane-World Cosmology
  We find two types [called (S) and (A)] of new vacuum solutions of open, flat, and closed universes which are inflating in the brane-world scenario. We show that the warp factor of the stabilized metric is universal for the three different kinds of universes. For (S) type solution, we show that one positive-tension brane universe solution is admitted as well as two positive tension brane solution even if we consider the vacuum solution. For (A) type solution, we find that the inflating bulk solutions have black hole like regions and that the full extended space is the R-S solution. 
Hyeong-Chan Kim, Jae Hyung Yee, and Mu-In Park