each of them produces, of an identical product.

因为他们生产的是同质的商品
So as far as the consumers are concerned,

对于消费者而言
these two products are perfect substitutes.

这两种商品是完全替代品
You could think of these as two companies producing bottled water

把他们想象成两家瓶装水厂商吧
and now we're going to get hundreds of letters

我估计我们会收到数百封信件
saying not all bottled waters are the same,

告诉我说不是所有瓶装水都是一样的
especially from Italians and the French,

尤其是从意大利和法国寄过来的那些
but never mind. Let's just pretend that they are.

无所谓了就把它们想象成是同质的吧
So just to emphasize that the strategies are quantities,

为了突出策略就是商品的产量
rather than using S let me use Q today to be the strategies.

这次我们用Q来表示策略而不用S了
So qi and q-i or q1 and q2 will be the strategies.

用qi q-i q1 q2表示策略
We need to give a little bit more structure on the payoff

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