These attempts can be split into four broad categories: Straightforward alternatives to general relativity (GR), such as the Cartan, Brans–Dicke and Rosen bimetric theories.
Bunlar kabaca dört gruba ayrılabilir: Doğrudan Genel Relativite'ye (GR) alternatifler: Bunlar Cartan, Brans–Dicke ve Rosen bimetric teorileri.