Ibáñez i Insa, JordiVerdaguer Oms, Enric, 1950-2010-05-062010-05-0619860556-2821https://hdl.handle.net/2445/12403We solve Einsteins equations in an n-dimensional vacuum with the simplest ansatz leading to a Friedmann-Robertson-Walker (FRW) four-dimensional space time. We show that the FRW model must be of radiation. For the open models the extra dimensions contract as a result of cosmological evolution. For flat and closed models they contract only when there is one extra dimension.3 p.application/pdfeng(c) The American Physical Society, 1986Relativitat general (Física)Teoria de camps (Física)CosmologiaEquacions d'EinsteinSolucions numèriquesTeoria de Kaluza-KleinGeneral relativity (Physics)Field theory (Physics)CosmologyEinstein field equationsNumerical solutionsKaluza-Klein theoriesinfo:eu-repo/semantics/article79595info:eu-repo/semantics/openAccess