2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/180577Exact solutions with an exponential behaviour of the scale factors are considered in a multidimensional cosmological model describing the dynamics of n+1 Ricci-flat factor spaces M_i in the presence of a one-component perfect fluid. The pressures in all spaces are proportional to the density: p_i = w_i ρ, i = 0,...,n. Solutions with accelerated expansion of our 3-space M_0 and a small enough variation of the gravitational constant G are found. These solutions exist for two branches of the parameter w_0. The first branch describes superstiff matter with w_0 > 1, the second one may contain phantom matter with w_0 < - 1.6 pages, Latex, G&C style, few typos correctedHigh Energy Physics - TheoryAstrophysicsGeneral Relativity and Quantum Cosmologytext