2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/2305I describe a new class of quintessence+CDM models in which late time scalar field oscillations can give rise to both quintessence and cold dark matter. Additionally, a versatile ansatz for the luminosity distance is used to reconstruct the quintessence equation of state in a model independent manner from observations of high redshift supernovae.4 pages, 2 figures. To appear in Proceedings of IAU Symposium 201, `New Cosmological Data and the Values of the Fundamental Parameters', Manchester, U.K., August 2000, eds. A.N. Lasenby and A. Wilkinson, Publications of the Astronomy Society of the PacificAstrophysicsGeneral Relativity and Quantum CosmologyHigh Energy Physics - Phenomenologytext