This chapter deals with some basic definitions and operations involving sets. These are summarised below:

A set is a well-defined collection of objects.

A set which does not contain any element is called empty set.

A set which consists of a definite number of elements is called finite set, otherwise, the set is called infinite set.

Two sets A and B are said to be equal if they have exactly the same elements.

A set A is said to be subset of a set B, if every element of A is also an element of B. Intervals are subsets of R.