A perpetuity is an asset or a contract that pays a fixed amount of money each time period, forever.

永续年金是一种财产或者合同,规定在每一时间段内,支付一定数量的货币,直至永远

耶鲁公开课 - 金融市场课程节选

This is a formula that applies to-- what if an asset pays a fixed amount every period and then stops?

这个公式应用于...,如果一份资产在每段时期都给与支付,然后突然停止了怎么办

耶鲁公开课 - 金融市场课程节选

You rotate the letters by a deterministic amount, by a fixed number of steps so that the end result is actually something that can be reversed.

你用确定的数量旋转那些字母，通过一个固定数量的步骤,这样，最终结果是可以把它,反加密出来。

哈佛公开课 - 计算机科学课程节选

You pay every year a fixed amount on your house to the mortgage originator and then after so many-- n is 30 years, typically--you would then have paid it off.

你每年都在你的房子上支付一定数目的偿款,给抵押商然后,数年后,设n是30年,一般来说你已经能偿清贷款了

耶鲁公开课 - 金融市场课程节选