Set Theory

Last Updated : 20 Jun, 2026

Set theory is a branch of mathematics that deals with collections of objects, called sets. A set is simply a collection of distinct elements, such as numbers, letters, or even everyday objects, that share a common property or rule.

Example of Sets

  • A set of fruits: {apple, banana, orange}
  • A set of numbers: {1, 2, 3, 4}
  • A set of even numbers: {2, 4, 6, 8, 10, ....}
  • A set of months with exactly 6 Sundays: {∅}. This set is empty, as no month has exactly 6 Sundays.

Foundations

The basics explained with examples and symbols.

Set Relationships

This section explains how sets relate to one another.

Operations & Visualization

Combining, comparing, and visualizing sets

Practice

Solved questions, quizzes, and practice problems to test your understanding.

Programs of Set Theory

How sets work in C++, Python, C#, and JavaScript using built-in set data structures.

Standard Problems Associated with Set Data Structure

Common set-based DSA problems: unions, intersections, duplicates, and more.

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