  We present a formalism for analysis of linear Cauchy data on a Kottler
metric. Our method removes redundancy due to gauge transformations and
constraints. A set of four gauge-invariant, scalar functions on the Cauchy
surface is produced and shown to contain full physical information from the
initial data. The symplectic form of the theory and equations of motion are
reformulated in terms of these invariants and some simple solutions are
explored.
