Five-card majors for offensive purposes. However, if the trump cards break 4-1 or 1-4, then drawing trump will result in no trumps left for offensive purposes. The value of five-card majors can be understood then on two levels: But five-card majors have several drawbacks: Both partners must agree to follow the five-card major bidding treatment on their opening bid. Opener must have at least five cards in hearts or spades to start the bidding with that suit. Responder is expected to show support with three-card support, indicating an eight-card fit. With only four cards in a major suit, the opening bidder is
Auction without a "reservation price" (or "reserve"), with the item sold to the highest bidder. Auctions are publicly and privately seen in several contexts and almost anything can be sold at auction. Some typical auction arenas include the following: Although less publicly visible, the most economically important auctions are the commodities auctions in which the bidders are businesses even up to corporation level. Examples of this type of auction include: Katehakis and Puranam provided the first model for the problem of optimal bidding for a firm that in each period procures items to meet a random demand by participating in a