Some aspects of field equations in generalised theories of gravity
  A class of theories of gravity based on a Lagrangian which depends on the
curvature and metric - but not on the derivatives of the curvature tensor - is
of interest in several contexts including in the development of the paradigm
that treats gravity as an emergent phenomenon. This class of models contains,
as an important subset, all Lanczos-Lovelock models of gravity. I derive
several identities and properties which are useful in the study of these models
and clarify some of the issues that seem to have received insufficient
attention in the past literature.
