What are these symbols used for? I do not understand these symbols. 


*

*a.s.

*e.g.

*i.e.

*c.f.

*...


See Wikepedia for a nice list of mathematical abbreviations.
Mathematically, a.s. is used to shorten "almost surely."
And a.e. is used to shorten "almost everywhere."
You might also want to consult the list of mathematical jargon, particularly if English isn't your native language, and even if it is!
