Recovering the effective cosmological constant in extended gravity theories
arXiv:gr-qc/9804053 · doi:10.1023/A:1026651129626
Abstract
In the framework of extended gravity theories, we discuss the meaning of a time dependent "cosmological constant" and give a set of conditions to recover asymptotic de Sitter behaviour for a class of cosmological models independently of initial data. To this purpose we introduce a time-dependent (effective) quantity which asymptotically becomes the true cosmological constant. We will deal with scalar-tensor, fourth and higher than fourth-order theories.
24 pages, Latex, submitted to Gen.Rel.and Grav