1. RSD
2. Next, recall that ? * ? v (seller can charge v) and W = ? RSD . us W = v implies ? RSD ? ? * , and equality must hold. Conversely suppose W = ? RSD = ? * , then W = p * (1 ? G(p * )). is implies p * ? W . Consider a seller who charges price p * against the Roesler-Szentes information structure F B W . By the unit elasticity of demand property, the seller's proot is either W = ? * (when p * < B) or 0. Since we showed in our main model that the seller can guarantee;Proof of Lemma 10. e inequality ? RSD ? ? * is obvious