A set is one of the fundamental concepts of mathematics, so it is accepted without definition. A set is a collection of objects that have some common property.In mathematics, a set is denoted by the capital letters of the Latin alphabet. The elements of a set are written in lowercase letters of the Latin alphabet. Sets are represented as follows: the empty set, the subset of sets, the union (sum) of sets, the intersection (product) of sets, the difference of sets, and theCartesian product of sets.