Notation varies depending on the author and subject area but a good resource for "programmer/computer science" notation is to skim through Concrete Mathematics

Notation varies depending on the author and subject area but a good resource for "programmer/computer science" notation is to skim through Concrete Mathematics or the preliminaries to The Art of Computer Programming -- I find this notation to be common. In more specialized areas like type theory, first order logic, predicate calculus, temporal logic, etc you have to pick it up as you go.