On the consistency of universally non-minimally coupled $f(R,T,R_{\mu \nu }{T}^{\mu \nu })$ theories

Ismael Ayuso, Jose Beltran Jimenez, Alvaro de la Cruz Dombriz

We discuss the consistency of a recently proposed class of theories described by an arbitrary function of the Ricci scalar, the trace of the energy-momentum tensor and the contract…