  We disprove Holtz and Ron's conjecture that the power ideal C_{A,-2} of a
hyperplane arrangement A (also called the "internal zonotopal space") is
generated by A-monomials. We also show that, in contrast with the case k \geq
-2, the Hilbert series of C_{A,k} is not determined by the matroid of A for k
\leq -6.
