每日钉一下（投资是零和游戏吗？）

Group 1 - The article highlights that most investors are familiar with stock index funds but have limited knowledge about bond index funds and their investment strategies [2] - A free course is offered to educate investors on how to invest in bond index funds, including course notes and mind maps for efficient learning [2] Group 2 - The concept of zero-sum games is explained, where one party's gain is another party's loss, exemplified by a simple game of rock-paper-scissors [6] - In contrast, investing in stock funds is described as a positive-sum game, where all participants can achieve collective gains due to the profitability of the underlying companies [7]