But, on the other hand, you don't want high variance because that's risk; so, both of those matter.

但另一方面，你不想要高水平的方差,因为它代表风险;,因此这两个参数都很重要。

耶鲁公开课 - 金融市场课程节选

Once you've got them together, then you can compute the efficient portfolio frontier without the riskless asset.

当你明确了这些参数后，就可以算出没有无风险资产情况下的,有效边界了。

耶鲁公开课 - 金融市场课程节选