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

A (2m + 1)-dimensional Einstein-Gauss-Bonnet (EGB) model with the cosmological term 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. © 2019 World Scientific Publishing Company.