2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/189520The dimensional reduction of $D$-dimensional spacetimes arising in string/M-theory, to the conformal Einstein frame, may give rise to cosmologies with accelerated expansion. Through a complete analysis of the dynamics of doubly warped product spacetimes, in terms of scale invariant variables, it is demonstrated that for $D \geq 10$, eternally accelerating 4-dimensional $κ= -1$ Friedmann cosmologies arise from dimensional reduction on an internal space with negative Einstein geometry.23 pages, 5 figures; references/comments addedHigh Energy Physics - TheoryGeneral Relativity and Quantum Cosmologytext