Introduction
A set is an unordered collection of objects. These objects are called elements or members of the set. Usually, uppercase letters (e.g., $A, B, C$) denote sets and lowercase letters (e.g., $a, b, c$) denote elements.
A set is an unordered collection of objects. These objects are called elements or members of the set. Usually, uppercase letters (e.g., $A, B, C$) denote sets and lowercase letters (e.g., $a, b, c$) denote elements.