Exact exponential cosmological solutions with two factor spaces of dimension m in EGB model with a Λ-term.

A (2 m + 1) -dimensional Einstein–Gauss–Bonnet (EGB) model with the cosmological term Λ is considered. We find a class of solutions with exponential time dependence of two scale factors, governed by two Hubble-like parameters H > 0 and h , corresponding to two factor spaces of dimension m > 2 and obeying H ≠ ± h. We prove that the solutions, obeying h / H ≠ − m − 1 m − 2 , − m − 2 m − 1 , are stable (in a class of cosmological solutions with diagonal metrics) for h > − H and they are unstable for h < − H. A subclass of solutions with small enough variation of the effective gravitational constant G is considered. It is shown that all solutions from this subclass are stable. [ABSTRACT FROM AUTHOR]