Perhaps as important is the relation between the existence of solutions to a competitive equilibrium and the problems of normative or welfare economics.

国君自以为神圣聪明，而不去咨询官吏，自以为国家安定强大，而不注重防守，周围的邻国图谋侵略他却不知道戒备。 

我年轻时领略过一种高尚的情操，我至今不能忘掉，这是我的烦恼。