  Parameterized representations of the equation of state play an important role
in efforts to measure the properties of the matter in the cores of neutron
stars using astronomical observations. New representations are presented here
that are capable of representing any equation of state to any desired level of
accuracy, while automatically imposing causality and thermodynamic stability
constraints. Numerical tests are presented that measure how accurately and
efficiently these new parameterizations represent a collection of causal
nuclear-theory model equations of state.
