- Fundamental operations
- intersection; “and”
- union; “or”
- Cardinality of intersections and union
- Venn diagram for union
2.2 Essential Ideas
Operations with Sets
Remember the basic operations:
The complement of a set S is consists of everything that is not in S.
The union of two sets is everything that is in either set; that is, anything colored
(blue, yellow, or green).
The intersection of two sets is everything that is in both sets; that is, anything
colored both blue and yellow, namely green.
Cardinality of Intersections and Unions
The cardinality of an intersection is the number of elements in the intersection.
The cardinality of a union is the sum of the cardinalities of the given sets
less the number of elements in the intersection.