The intersection of two sets is the new set formed by taking those elements that are
contained in both sets. If A and B are sets, then their intersection is written
A∩B. As a result of this definition, A∩B is a subset of both A and B.
Compare to the unionA∪B, which is the collection of elements contained in either set.
In the standard figure below, two sets are represented by circles (shaded white), and their intersection
has been shaded red.