Further Extended Theories of Gravitation: Part I

Understand

We shall here propose a class of relativistic theories of gravitation, based on a foundational paper of Ehlers Pirani and Schild (EPS).All "extended theories of gravitation" (also known as f(R) theories) in Palatini formalism are shown to belong to this class.

• In a forthcoming paper we shall show that this class of theories contains other more general examples.
• EPS framework helps in the interpretation and solution of these models that however have exotic behaviours even compared to f(R) theories.