Higher-Order Gauss-Bonnet Cosmology

Understand

We study cosmological models derived from higher-order Gauss-Bonnet gravity $F(R,G)$ by using the Lagrange multiplier approach without assuming the presence of additional fields with the exception of standard perfect fluid matter.

• The presence of Lagrange multipliers reduces the number of allowed solutions.
• We need to introduce compatibility conditions of the FRW equations, which impose strict restrictions on the metric or require the introduction of additional exotic matter.
• Several classes of $F(R,G)$ models are generated and discussed.