The Combinatorial Clock Auction is a two-stage auction format, which has been used to sell spectrum licenses worldwide in the recent years. It draws on a number of elegant ideas inspired by economic theory. A revealed preference activity rule should provide incentives to bid straightforward,...

Motivated by markets for television advertising time-slots, we introduce a new combinatorial auction format, including a general method for approximating core-selecting payments for hard problems. Given the size and complexity of ad markets in practice, an enumerative XOR bidding language...