Serious 3NT Serious 3NT Serious 3NT is a contract bridge bidding convention. It is used in game-forcing auctions where a major suit has been agreed upon. 1–2 if using 2/1 Game Forcing or 2–3 (Agreeing spades) The next bid indicates suitability for slam: Since Spades are the agreed trump suit, Three No Trump is not usually the best contract. Using Serious Three No Trump, a bid of Three No Trump says "I am Serious about slam", i.e. "I have a good hand". Bypassing bidding Three No Trump says "I am not Serious about Slam". Examples shown in the above auction. If one
Vickrey auction is dominated by the strategy of truthfully bidding. The strategy of underbidding is dominated by bidding truthfully. Assume that bidder i bids formula_8. If formula_9 then the bidder would lose the item with a truthful bid as well as an underbid, so the strategies have equal payoffs for this case. If formula_10 then the bidder would win the item either way so the strategies have equal payoffs in this case. If formula_11 then only the strategy of truthfully bidding would win the auction. The payoff for the truthful strategy would be positive as they paid less than their value of