Bidding Languages and Winner Determination for Mixed Multi-unit Combinatorial Auctions

We introduce a new type of combinatorial auction that allows agents to bid for goods to buy, for goods to sell, and for transformations of goods. One such transformation can be seen as a step in a production process, so solving the auction requires choosing the sequence in which the accepted bids should be implemented. We introduce a bidding language for this type of auction and analyse the corresponding winner determination problem.