The fundamental model of duopoly competition in vertical differentiated market has two very important assumptions: consumers' information is complete and their preferences are stable.

基本的纵向差异化下的双寡头竞争模型有两个很重要的假设：消费者信息完全与偏好稳定。

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Polling since the debate generally shows small or no shifts in the vote preference of all registered voters, but big shifts in enthusiasm, and better margins after a likely voter screen. (Pew is the exception, and apparent outlier.) Vote preferences have remained remarkably stable despite overwhelming and near-universal negative post-debate coverage of the President.

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