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

So Coca-Cola and Poland Spring could just agree to produce half the quantity of water each.

假如可口可乐和波兰泉达成默契了,同意各产垄断产量的一半

耶鲁公开课 - 博弈论课程节选