  We derive lower limits on the inefficiency and classical communication costs
of dilution between two-term bipartite pure states that are partially
entangled. We first calculate explicit relations between the allowable error
and classical communication costs of entanglement dilution using the protocol
of Lo-Popescu and then consider a two-stage dilution from singlets with this
protocol followed by some unknown protocol for conversion between partially
entangled states. Applying the lower bounds on classical communication and
inefficiency of Harrow-Lo and Hayden-Winter to this two-stage protocol, we
derive bounds for the unknown protocol. In addition we derive analogous (but
looser) bounds for general pure states.
