Compactifying the state space for alternative theories of gravity

In this paper, we address important issues surrounding the choice of variables when performing a dynamical systems analysis of alternative theories of gravity. We discuss the advantages and disadvantages of compactifying the state space and illustrate this using two examples. We first show how to define a compact state space for the class of LRS Bianchi type I models in Rn-gravity and compare to a non-compact expansion-normalized approach. In the second example we consider the flat Friedmann matter subspace of the previous example, and compare the compact analysis to studies where non-compact non-expansion-normalized variables were used. In both examples, we comment on the existence of bouncing or recollapsing orbits as well as the existence of static models