Brane-Universe in Six Dimensions with Two Times
  Brane-Universe model embedded in 6-dimensional space-time with the signature (2+4) is considered. A matter is gravitationally trapped in three space dimensions, but both time-like directions are open. Choosing of the dimension and the signature of the model is initiated with the conformal symmetry for massless particles and any point in our world can be (1+1) string-like object. 
Merab Gogberashvili