Group 1 - The article discusses the influence of various stock trading theories in the A-share market, particularly focusing on the "follow the main force" theory and trend-following theory [1][6]. - It highlights the perception of "main force" or "庄家" as a powerful entity in the stock market, with many believing that following them can lead to significant profits [1][5]. - The article questions the effectiveness of the "follow the main force" theory, citing examples of public and private funds that often incur losses, indicating that even established players are not infallible [4][5]. Group 2 - The article explains that the "follow the main force" theory is not universally applicable, as multiple main forces can exist within a single stock, leading to conflicting interests [5]. - It points out the reasons for the enduring influence of the "follow the main force" theory, including its unverifiability and the psychological reliance of investors on such theories for certainty [6][7]. - In contrast, the trend-following theory focuses on the overall market direction rather than individual players, suggesting that understanding market forces can lead to more consistent trading success [8][9].