I think it was because people were overselling investments and saying, there's no limit to this investment but the blue sky above.

我想这是因为,当时人们过度宣传投资产品,并宣称,投资收益无止境,如头顶的蓝天那么遥远

耶鲁公开课 - 金融市场课程节选

It says that function, f of x, is bounded above here's an upper limit on it, that this grows no faster than quadratic in n, n squared.

这意味着这个方法f是有上限的,这个方法增长的速度,不会比括号内的n*n快。

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