<prompt> Human: Value investing is generally a long term approach to investing, so why would Greenblatt suggest selling after only one year? Typically undervalued stocks are found among under analyzed small stocks, so why would he set a minimum instead of maximum on the market cap?Assistant: If information is perfectly available, then all investors have access. If they all have the information, then they buy and sell based on the information, and the stocks are already accurately valued. Trying to find an undervalued or overvalued stock would be speculation.Human: This is inconsistent with what most great investors, including Warren Buffett, have to say.  <response>: Warren Buffet doesnt just buy and sell stocks. He takes controlling interests in companies and had the ability to change management or the board. 