We study brane-world solutions of five-dimensional supergravity in singular
spaces. We exhibit a self-tuned four-dimensional cosmological constant whe
n five-dimensional supergravity is broken by an arbitrary tension on the br
ane-world. The brane-world metric is of the FRW type corresponding to a cos
mological constant Omega (Lambda) = 5/7 and an equation of state omega = -5
/7 which are consistent with experiment. (C) 2001 Elsevier Science B.V. All
rights reserved.