# What is set theory

Dear Student,
A detailed solution to your query is provided below :

​​​​A set is a collection of distinct objects.There are are often specified with curly brace notation. for example - {1, 2, 3} . The study of these sets and their relationships comes under Set Theory.Various important terms and defination included in Set Theory are :

​​​​​​1.Empty set - is a set containing no objects. It is written as a pair of curly braces with nothing inside { } or by using the symbol ∅.

2.The set membership symbol - ∈ is used to say that an object is a member of a set. Example - If S = {1, 2, 3} then 3 ∈ S .

3.The cardinality of a set is its size. For a finite set, the cardinality of a set is the number of members it contains.

4.The intersection of two sets S and T is the collection of all objects that are in both sets. It is written S ∩ T . Using curly brace notation S ∩ T = {x : (x ∈ S) and (x ∈ T )}

5.The union of two sets S and T is the collection of all objects that are in either set. It is written S ∪ T . Using curly brace notion S ∪ T = {x : (x ∈ S) or (x ∈ T )}

Regards.

• 0
What are you looking for?