Subsets

If A is a subset of B then every ekement in A is in B.

A={1,2}

B={1,2,3,4,5}

We write:

It is legal for A to have all the elements in B.

If we say A is a Proper Subset then there must be at least one element of B not present in A.

The Power Set of S is the set containing all subsets of S.

Consider the set S={1,2,3}.

All possible subsets of S are shown below.

• 
• {1}
• {2}
• {3}
• {1,2}
• {1,3}
• {2,3}
• {1,2,3}