We start the new chapter on Probability of Simple Events. Today we study the notation of set.

We use the term set to mean a collection of well-defined distinct objects. The objects in a set are called elements or members. Note, a set only contains distinct elements, no duplicates, and the order in which the element appear is insignificant.

Two sets A and A are equal, written as A = B, if they have exactly the same elements.

If every element of a set A is also an element of a set B, then A is said to be a subset of B. And if A is a subset of B, but A is not equal to B, then A is said to be a proper subset of B.

We define a universal set as an overall set of a particular problem when all sets for the problem are subsets of this set. Note, different problems may have different universal sets, and a problem can have more than one universal set.

We also define the empty set which contains no elements and is a subset of any set.

Last we define  the compliment of a set A as the set that contains elements that do not belong to the set A but belong to a universal set of A.

Note, pretty everything we study is by definition, so it is important that students understand the definitions.

Homework:

Page 57, #1 – #6, #17 – #20.