Exact Cosmological Solutions of Nonlinear F(R)-Gravity

TL;DR

This paper reviews the current understanding of exact solutions in nonlinear F(R)-gravity, discussing their properties, singularities, and simplifications through conformal relations, while highlighting open questions for future research.

Contribution

It provides a comprehensive overview of exact solutions in nonlinear F(R)-gravity and explores methods to analyze their properties and open questions for future studies.

Findings

Discussion on the nature of solutions without closed-form expressions

Analysis of singularities in F(R)-gravity solutions

Role of conformal relations and dimensional reductions

Abstract

We report on the cited papers refs. 1 - 18 from the following points of view: What do we exactly know about solutions when no exact solution (in the sense of "solution in closed form") is available? In which sense do these solutions possess a singularity? In which cases do conformal relations and/or dimensional reductions simplify the deduction? Furthermore, we outline some open questions worth of being studied in future research.