Abstract: A seller may sell advertisements, such as banner ads, to a buyer pursuant to a request made by the buyer to the seller. Each request has a value. The seller may accept the request from the buyer to provide a banner ad for the buyer at a later time. A request, once accepted, may be revoked at a cost which may be a fixed fraction of the request value. The cost may be referred to as a buyback cost. The buyback cost represents the cost of revoking a request that had been accepted. Additionally, matroid set systems and knapsack systems may use buyback techniques.

Abstract: An auction may include a general schema to create incentives for those agents or bidders to bid on items at auction truthfully. The schema may implement any allocation rule, including a monotone allocation rule. The schema may provide for accepting bids from bidders, transforming the bids in a manner appropriate to the item being auctioned, and applying the allocation rule on the transformed bid. The schema may further provide for providing a rebate or payment back to the bidders.

Abstract: A seller may sell advertisements, such as banner ads, to a buyer pursuant to a request made by the buyer to the seller. Each request has a value. The seller may accept the request from the buyer to provide a banner ad for the buyer at a later time. A request, once accepted, may be revoked at a cost which may be a fixed fraction of the request value. The cost may be referred to as a buyback cost. The buyback cost represents the cost of revoking a request that had been accepted. Additionally, matroid set systems and knapsack systems may use buyback techniques.