1. Mathematically, the intersection of two sets A and B is a set that contains all the elements belonging to A and B, but does not contain other elements.

2. the intersection of a and b is written as A ∩B B formally: x belongs to A ∩B if and only if x belongs to a and x belongs to B.

3. For example, the intersection of sets {1, 2,3} and {2,3,4} is {2,3}. The number 9 does not belong to the intersection of the prime set {2,3,5,7, 1 1} and the odd set {1, 3,5,7,9,1}.

4. If the intersection of two sets A and B is empty, that is, they have no common elements, then they do not intersect.

5. More generally, intersection operations can be performed on multiple sets at the same time. For example, the intersection of sets a, b, c and d is a ∩ b ∩ c ∩ d = a ∩ (b ∩ (c ∩ d)). The intersection operation satisfies the associative law, that is, a ∩ (b ∩ c) = (a ∩ b) ∩ c c.