The change of labor productivity also can cause the change of the commodity supply and demand relations thus the total value quantity is changed.

同时，劳动生产率变化还会使商品供求关系变化，从而使价值总量发生变化。

youdao

So total quantity demand is 1 -P where P is the lower of the two prices.

总需求量是1-P,而P是两个公司的价格中较低那个

耶鲁公开课 - 博弈论课程节选