  We show that a large fraction of the data-structure lower bounds known today
in fact follow by reduction from the communication complexity of lopsided
(asymmetric) set disjointness. This includes lower bounds for:
  * high-dimensional problems, where the goal is to show large space lower
bounds.
  * constant-dimensional geometric problems, where the goal is to bound the
query time for space O(n polylog n).
  * dynamic problems, where we are looking for a trade-off between query and
update time. (In this case, our bounds are slightly weaker than the originals,
losing a lglg n factor.)
  Our reductions also imply the following new results:
  * an Omega(lg n / lglg n) bound for 4-dimensional range reporting, given
space O(n polylog n). This is quite timely, since a recent result solved 3D
reporting in O(lglg n) time, raising the prospect that higher dimensions could
also be easy.
  * a tight space lower bound for the partial match problem, for constant query
time.
  * the first lower bound for reachability oracles.
  In the process, we prove optimal randomized lower bounds for lopsided set
disjointness.
