  arXiv:1205.2953 defines an entropy for a gaussian scalar field $\phi$ in an
arbitrary region of either a causal set or a continuous spacetime, given only
the correlator $\langle\phi(x)\phi(y)\rangle$ within the region. As a first
application, we compute numerically the entanglement entropy in two cases where
the asymptotic form is known or suspected from conformal field theory, finding
excellent agreement when the required ultraviolet cutoff is implemented as a
truncation on spacetime mode-sums. We also show how the symmetry of
entanglement entropy reflects the fact that $RS$ and $SR$ share the same
eigenvalues, $R$ and $S$ being arbitrary matrices.
