Higher dimensional massive bigravity
  We study higher dimensional scenarios of massive bigravity, which is a very
interesting extension of nonlinear massive gravity since its reference metric
is assumed to be full dynamical. In particular, the Einstein field equations
along with the following constraint equations for both physical and reference
metrics of a five-dimensional massive bigravity will be addressed. Then, we
study some well-known cosmological spacetimes such as the
Friedmann-Lemaitre-Robertson-Walker, Bianchi type I, and
Schwarzschild-Tangherlini metrics for the five-dimensional massive bigravity.
As a result, we find that massive graviton terms will serve as effective
cosmological constants in both physical and reference sectors if a special
scenario, in which reference metrics are chosen to be proportional to physical
ones, is considered for all mentioned metrics. Thanks to the constancy property
of massive graviton terms, consistent cosmological solutions will be figured
out accordingly.
