| Intersection. Given two sets A and B, A ∩ B is the set of all elements of A that are also elements of B. If there are no common members between A and B, A ∩ B consists of the empty set. A rather simplistic example of intersection:
A = { 1, 2, 3, 5 }
B = { 1, 2, 3, 4 }
A ∩ B = {1, 2, 3}
∩ is written in HTML as ∩
See also: ∪ | 
