High Quality Content by WIKIPEDIA articles! In mathematics, the limit of a sequence of sets A1, A2, ... is a set whose elements are determined by the sequence in either of two equivalent ways. In mathematics, the concept of a "limit" is used to describe the value that a function or sequence "approaches" as the input or index approaches some value. Limits are essential to calculus (and mathematical analysis in general) and are used to define continuity, derivatives and integrals. The concept of the limit of a function is further generalized to the concept of topological net, while the limit of a sequence is closely related to limit and direct limit in category theory.