摘要：Consider any investor who fears ruin facing any set of invest-ments that satisfy no-arbitrage. Before investing, he can purchase informa-tion about the state of nature in the form of an information structure. Givenhis prior, information structure α is more informative than information struc-ture β if whenever he rejects α at some price, he also rejects β at that price.We show that this complete informativeness ordering is represented by thedecrease in entropy of his beliefs, regardless of his preferences, initial wealthor investment problem. It is also shown that no prior-independent informa-tiveness ordering based on similar premises exists
关键词：informativeness; information structures; entropy; decision under;uncertainty; investment; Blackwell ordering
