Ví dụ công khai
Auctions come in a wide variety. In a “Dutch auction”, often used to sell flowers and fruit, prices start high and gradually drop until a bidder is willing to pay up. A “Japanese auction” is a bit like poker: bids rise with each round and anyone who wants to win must bid every time. Vendors using auctions rid themselves of the headache of choosing prices and instead just pick the rules bidders must follow.