Cosmological reconstruction and energy bounds in $$f(R,R_{\alpha \beta }R^{\alpha \beta },\phi )$$ f ( R , R α β R α β , ϕ ) gravity

R-complex Finsler Spaces with (α, Β)-metric

In this paper we introduce the class of R-complex Finsler spaces with (α, β)-metrics and study some important exemples: R-complex Randers spaces, R-complex Kropina spaces. The metric tensor field of a R-complex Finsler space with (α, β)-metric is determined (§2). A special approach is dedicated to the R-complex Randers spaces (§3). AMS Mathematics Subject Classification (2000): 53B40, 53C60

T ∆(B−V)I ∆α ∆(B−V)O ∆α ∆(B−R)I ∆α ∆(B−R)O ∆α ∆(V −R)I ∆α ∆(V −R)O ∆α Break

Cosmological Dynamics from Modified f(R) Gravity in Einstein Frame

In this paper, we investigate and analyze the cosmological dynamics of the universe, with an effect of modified f(R) gravity emerging at cosmological scale. We choose the Einstein frame as a physical frame. We consider phase portraits of the universe at the late time from modified f(R) gravity model. This result gives our universe an acceleration phase expansion without introducing existence of...

Stability of cosmological solutions in f R models of gravity

Ignacy Sawicki and Wayne Hu* Kavli Institute for Cosmological Physics, University of Chicago, Chicago, Illinois 60637, USA Enrico Fermi Institute, University of Chicago, Chicago, Illinois 60637, USA Department of Physics, University of Chicago, Chicago, Illinois 60637, USA Department of Astronomy & Astrophysics, University of Chicago, Chicago, Illinois 60637, USA (Received 9 February 2007; publ...

Beta Regression in R

This introduction to the R package betareg is a (slightly) modified version of CribariNeto and Zeileis (2010), published in the Journal of Statistical Software. A follow-up paper with various extensions is Grün, Kosmidis, and Zeileis (2012) – a slightly modified version of which is also provided within the package as vignette("betareg-ext", package = "betareg") The class of beta regression mode...