Understanding Subsets
In set theory, a set A is a subset of set B if every element of A is also an element of B. This fundamental concept is central to discrete mathematics, logic, and computer science.
Set Relationships
Subset (\u2286)
A \u2286 B means every element in A is also in B. A can equal B.
{1,2} \u2286 {1,2,3} is TRUE
Proper Subset (\u2282)
A \u2282 B means A \u2286 B and A \u2260 B (B has at least one extra element).
{1,2} \u2282 {1,2,3} is TRUE
Superset (\u2287)
B \u2287 A means B contains all elements of A. Reverse of subset.
{1,2,3} \u2287 {1,2} is TRUE
Set Operations
- Intersection (A \u2229 B): Elements common to both A and B.
- Union (A \u222A B): All elements in A or B or both.
- Difference (A \\ B): Elements in A but not in B.
- Symmetric Difference (A \u2206 B): Elements in A or B but not both.
Properties of Subsets
- The empty set \u2205 is a subset of every set.
- Every set is a subset of itself (A \u2286 A).
- If A \u2286 B and B \u2286 A, then A = B.
- If A \u2286 B and B \u2286 C, then A \u2286 C (transitivity).