set
The mathematical set is traditionally known as a collection of objects. It is one of the most general and useful structures in mathematics.
Z = the set of integer numbers... {...-1, 0, 1...} R = the set of real numbers (all non-complex numbers) Let Q be the set of people who understand this definition and let S be the set of people who care about this definition: Q intersect S is simply Q.
By alpsmac