Two(!) Good To Be ... Monotonic

(joint works with Ran Ben Moshe, Noam Nisan, and Yannai Gonczarowski)

Abstract: Selling multiple goods is a notoriously difficult problem. Inter alia, the following non-monotonicity phenomenon has been exhibited by Hart and Reny (2015): the willingness to pay of the buyer increases but the maximal revenue that the seller can extract decreases. We will show, first, that this effect is significant, and, second, that there is no way for the seller to mitigate it.