Sets

A set is a well

A set is a well-defined collection of objects. The rule for deciding whether an object belongs to the collection must be clear. For example, odd natur

In roster form

In roster form, elements are listed inside braces and the order does not matter. Repeated elements do not change the set. In set-builder form, the set

A set with no element

A set with no element is the empty set, also called the null set or void set. It is denoted by φ or { }. Examples include the set of rational solution

A finite set is empty

A finite set is empty or has a definite number of elements. An infinite set is not finite. The set of natural numbers is infinite, while the set of da

Two sets are equal if they

Two sets are equal if they have exactly the same elements. Order does not matter, and repeating elements does not change the set. If A and B have exac