Diagram with multiple entries in which the elements of a set are classified inside a rectangle that represents the universal set in order to reveal a subset and its complement.

Each area of the diagram contains elements that have shared characteristics.

In a Carroll diagram, the elements are sometimes represented by dots, and sometimes by pictograms, depending on the need.

### Example

This Carroll diagram presents the whole numbers 2 to 14 according to whether or not they belong to the set of prime numbers, the set of even numbers, or the set of divisors of 12:

### Historical Note

This diagram is named after Lewis Carroll (1832-1898), a British math teacher whose real name was Charles Lutwidge Dodgson, author of the tales *The Adventures of Alice in Wonderland* and *Through the Looking Glass*, in which Carroll used many complementary elements, opposites, and inversions.