2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/227511A non-trivial spatial topology of the Universe is a potentially observable attribute, which can be probed through the circles-in-the-sky for all locally homogeneous and isotropic universes with no assumptions on the cosmological parameters. We show how one can use a possible circles-in-the-sky detection of the spatial topology of globally homogeneous universes to set constraints on the dark energy equation of state parameters.6 pages, 1 figure. To appear in Int. J. Mod. Phys. A (2009). From a talk presented at the Seventh Alexander Friedmann International Seminar on Gravitation and CosmologyCosmology and Nongalactic AstrophysicsGeneral Relativity and Quantum CosmologyHigh Energy Physics - Theorytext