This document discusses the concept of limits in mathematics. It defines a limit as the value a function approaches as the input values get closer to a certain point, without actually reaching it. For a limit of a function f(x) as x approaches c to exist, the left-hand limit and right-hand limit must both exist and be equal to the same number L. A limit may not exist if the left and right sides are different, or if the values oscillate or approach infinity as x approaches c. The document also formally defines a limit using epsilon-delta notation.