Sets
A set is a collection of distinct numbers or objects. Each object is called an element or member of the set.
Intersection and Union
Two sets A and B are disjoint or mutually exclusive if they have no elements in common. The union of two sets are all the elements they have in common.
Compliments
The universal set U is the set of all elements we are considering. The complement of a set A is the set of all elements of U that are not elements of A. The complement of A is written A’.
Special Number Sets
- Natural, counting numbers (N)
- Integers (Z)
- Positive Integers (Z+)
- Rational Numbers (Q)
- Irrational Numbers (Q’) - Interesting!
- Real Numbers (R)
Interval Notation
To describe this set: {—2, —1, 0, 1, 2, 3, 4} Use the interval notation: {x € Z | -3 < x < 5}
Venn Diagrams
These are diagrams used to visually display the sets and their relationships.