  We show that, in a multi-party setting, two non-distillable (bound-entangled)
states tensored together can make a distillable state. This is an example of
true superadditivity of distillable entanglement. We also show that unlockable
bound-entangled states cannot be asymptotically unentangled, providing the
first proof that some states are truly bound-entangled in the sense of being
both non-distillable and non-separable asymptotically.
