Giffen

基本解释

Giffen goods concept is just logically possible.It can not be confirmed by fact.
应该是仍未被事实证明，而非不能。
So the Giffen good is not implausible purely on logical grounds, although Giffen goods are unlikely to be encountered in real-world behavior.
因此从纯逻辑的角度看,吉芬商品并非是不合理的,虽然在现实世界的行为中不可能遇到吉芬商品。
The straight dotted line indicates where the curves are kinked.The right panel illustrates the Giffen good effect, as the consumer's income is m = 5.
总之，无差异曲线不是凸向原点的曲线，是三角形两个边的那种线。
Law of demand assumes income effect is negligible, while income effect of giffen good is so strong that outweights substitution effect.
然则收入是无限大。不知现实世界有否此类情况存在？？
But if it is logically impossible for Giffen good to exist in a society(Cheung's view), the law of demand can therefore be derived.
鲁宾逊的世界不可能有市场或任何社会或制度的分配问题，但鲁宾逊有需求，也要付代价。