A Euler diagram is a way of representing sets and their relationships. They are particularly useful for explaining complex hierarchies and overlapping definitions.
Euler diagrams consist of simple closed shapes that each depict a set. How or whether these shapes overlap demonstrates the relationships between the sets. Objects in the interior of these shapes represents the elements of the set and objects on the exterior of the shape represents the elements not in the set.
Example Euler diagram of the complement of a set
, .
Example Euler diagram of the set difference between the sets
and , .
Example Euler diagram showing the relationship between different types of numbers (integers, naturals, rationals, and irrationals)