有一个英文解读问题，The active risk attributed to Active Share will be smaller for more diversified portfolios with lower idiosyncratic risk. 为什么active risk 可以贡献active share?逻辑不应该是active share contribute and correlation contribute active risk 吗？
还有一句话Active risk does rise with an increase in factor and idiosyncratic volatility. 非系统性风险增加active risk增加很OK，但是increase in factor为什么会增加active risk呢
