• Exact Solutions of the Field Equations for Empty Space in the Nash Gravitational Theory 

      Aadne, Matthew Terje; Grøn, Øyvind (Journal article; Peer reviewed, 2017-02)
      John Nash has proposed a new theory of gravity. We define a Nash-tensor equal to the curvature tensor appearing in the Nash field equations for empty space, and calculate its components for two cases: 1. A static, spherically ...
    • Universal spacetimes in four dimensions 

      Hervik, Sigbjørn; Pravda, Vojtech; Pravdova, Alena (Journal article; Peer reviewed, 2017-10)
      Universal spacetimes are exact solutions to all higher-order theories of gravity. We study these spacetimes in four dimensions and provide necessary and sufficient conditions for universality for all Petrov types except ...