【英语生活】8个人怎么分摊租金

I am moving into an eight-bedroom flat with seven friends in a few months and need to decide fair rates for each of the rooms. Assuming some people want cheaper rent and some want nicer rooms, what is the fairest way to split the total monthly rent of £3,200 and decide who gets what?

Student, St Andrews

Dear Student,

I have answered a very similar question before, but for three people rather than eight. My solution then - a modification of "one cuts, the other chooses" - would not work for you. Therefore I propose a simultaneous ascending auction of the largest seven rooms; whoever does not win one of the largest seven gets the smallest room at whatever rent is necessary to bring the total to £3,200.

Bidding proceeds in rounds. In the first round, any student may choose to bid on any of the seven largest rooms, in increments of £5. Ties are broken with the toss of a coin. In each subsequent round, students without rooms must submit a bid to exceed the current high bid by £5. Any incumbents thus dislodged can bid on any room in the following round.

The auction ends when seven students are incumbents in the seven rooms, and the eighth student does not wish to outbid any of them, but would rather take the small room and pay the balance of the £3,200. (If the bidding is frenetic enough, she may be paid to take the small room.)

At any time, roomless students have an incentive to bid on whichever room offers the best combination of price and quality - or to drop out if they think the smallest room looks cheap. But beware: such an auction is neither foolproof nor, if some players decide to collude, cheat-proof. Still, perfection is for mathematicians, not economists.

亲爱的经济学家：

几个月后，我将和7个朋友搬进一套有8间卧室的公寓中去，现在需要确定每间卧室的公平价格。假如有人希望租金便宜些，而有人想要更好的房间，那怎样才是分摊3200英镑月租并决定谁住哪一间的最公平方式呢？

学生，圣安德鲁斯大学(St Andrews)

亲爱的学生：

我以前曾回答过一个非常类似的问题，但那一次是3个人，而非8个。我当时的解决办法——“一人切，另一人选”(One Cuts, The Other Chooses)的修改版——对你们并不适用。因此，我建议对最大的7间卧室进行“同时上升拍卖”(Simultaneous Ascending Auction)；未能竞得其中任何一间的那个人，将得到该公寓最小的那间卧室，房租为其他7人支付的租金总额与3200英镑之间的差价。

整个竞价过程包括多轮出价。在第一轮，每个人都可以选择对7间卧室中的任何一间出价，加价幅度为5英镑。遇到相同的竞价时，以掷硬币的方式解决。在随后的每一轮中，未得标者必须以超过当前最高价5英镑的价格投标。以此方式被挤掉的得标者可在下一轮对任何房间投标。

当有7个人成为7间卧室的得标者、而第8个人宁愿选择最小的房间并补足3200英镑月租也不愿以更高出价挤掉这7人中的任意一人时，拍卖结束。（如果出价足够狂热，这第8个人还可能被倒找钱。）

在任何时候，未得标的人都有动力去投标性价比最高的房间——或在他们认为最小的房间看上去很便宜时选择退出。但要当心：这种拍卖既非绝对可靠，也无法防止欺诈——如果一些投标者决定串谋的话。不过，尽善尽美是数学家的事，与经济学家无关。

译者/陈云飞