论文阅读中经常遇到的一些缩写、简拼，具体含义
cf. 参考
例句：The prefix B denotes that the corresponding quantity is expressed in the frame B (cf., Fig. 2)
i.e. 即
例句：Inherently, the vision-only problem has six DoFs that are unobservable and need to be held fixed during optimization, i.e. the absolute pose.
s.t. 服从，满足 ，受约束于
subject to的缩写，通常出现在数学方程式和数学公式中，比如： 参数x满足约束g(x)=0的所有值中，使得f(x)的值最大。
e.g. 例如
源自拉丁文exempli gratia 例句：This is in contrast to, e.g., Sibley et al.
w.r.t.