Finite-time singularities in modified ℱ(R,g)-gravity and singularity avoidance

Abstract

We study finite-time future singularities in ℱ(R,G)-gravity, where R and G are the Ricci scalar and the Gauss-Bonnet invariant, respectively. In particular, we reconstruct the ℱ(G)-gravity and ℱ(R,G)-gravity models realizing the finite-time future singularities. We discuss a possible way to cure the finite-time future singularities in ℱ(R,G)-gravity by taking into account higher-order curvature corrections or effects of viscous fluids.