MATH 110 Lecture Notes - Lecture 4: Subset, Universal Set

• School: University of Alabama
• Department: MATH
• Course: MATH 110
• Professor: Qing Xiao

Document Summary

The set a is a subset of set b if every element in a is also an element in b. A is a proper subset of b if every element in a is also an element in b but a is not equal to b. denoted as: a b. If the set a contains any element that is not in set b, this it is not a subset. Is the relation between elements and sets. For any set a with cardinal number k written |a| = k, the number of subsets of a is ak, including and a. 5 {1, 2, 3, 4} in this example, 5 is an element and {1, 2, 3, 4} is a set. Let a = {1, 2, 3} and list all of the subsets of a. , {1}, {2}, {3}, {1, 2}, {1, 3}, {2, 3}, {1, 2, 3}