It's illegal to sign an agreement, to sign a contract saying you're going to restrict quantities.

签订这样限制产量的协议,属于违法行为

耶鲁公开课 - 博弈论课程节选

It's illegal, so they can't sign that as a contract, but they they can just agree to do it.

因为是违法的,合同也就无效了,不过他们可以私下达成默契

耶鲁公开课 - 博弈论课程节选

And so if you sign a contract with the government for millions of dollars, you have guarantee to get your dollars back, plus whatever profits they allowed in the contract.

所有如果你和政府签订了合约,做了一个百万的大单子，你能保证拿到钱，和其他的利润,在合同里规定的利润。

斯坦福公开课 - 经济学课程节选