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.