A Venn diagram is a schematic representation used in depicting collections of sets and the interrelationships between those sets. Although Venn diagrams are often employed in literary studies they are more common in mathematical studies involving the validity of deduction and proof. Physically, Venn diagrams are collections of intersecting, simple, two-dimensional polygons. The order of a Venn diagram n is often specified and refers to the number of simple closed curves.

A simple Venn diagram is one in which no two curves intersect in more than a finite number of points and no three or more curves intersect at one common point. This says that the curves defining sets meet at points and not in segments of curves. Below is an example of an order-three Venn diagram:

This particular diagram consists of three intersecting circles that are symmetrically placed and comprise a total of eight regions...