• Type III and II universal spacetimes 

      Hervik, Sigbjørn; Pravdova, Alena; Pravda, Vojtech (Journal article; Peer reviewed, 2015)
      We briefly summarize our recent results on universal spacetimes. We show that universal spacetimes are necessarily CSI, i.e. for these spacetimes, all curvature invariants constructed from the Riemann tensor and its ...
    • Type N universal spacetimes 

      Hervik, Sigbjørn; Pravda, V; Pravdova, A (Journal article; Peer reviewed, 2015)
      Universal spacetimes are vacuum solutions to all theories of gravity with the Lagrangian L [...]. Well known examples of universal spacetimes are plane waves which are of the Weyl type N. Here, we discuss recent results ...