Effective field theories have also been used to simplify problems in General Relativity, in particular in calculating the gravitational wave signature of inspiralling finite-sized objects.[3] The most common EFT in GR is "Non-Relativistic General Relativity" (NRGR),[4][5][6] which is similar to the post-Newtonian expansion.[7] Another common GR EFT is the Extreme Mass Ratio (EMR), which in the context of the inspiralling problem is called EMRI.