Empty, Null Set: p ={} 5Ug=5 s∩g= P Universal Set 5- P-s
Empty, Null Set: = { } S U = S S = S - = S - S = U = Universal Set
Subset A=(1,2,3} B={1,2,3,4,5} A cB Proper Subset A C B B A
Subset A = { 1, 2, 3} B = { 1, 2, 3, 4, 5 } A B U Proper Subset: A B U A B
Disjoint Sets A={1,2,3}B={5,6} A∩B=g A
Disjoint Sets A = { 1, 2, 3 } B = { 5, 6} A B = U A B
Set cardinali Ity · For finite sets A={2,5,7} A|=3 (set size)
Set Cardinality • For finite sets A = { 2, 5, 7 } |A| = 3 (set size)
Powersets A powerset is a set of sets s=a, b,c) Powerset of S= the set of all the subsets ofS, P(S), 2 2S={Q,{a},{b},{c},{a,b},{a,c},{b,c},{a,b,c}} Observation: 2S=2S(8=23)
Powersets A powerset is a set of sets Powerset of S = the set of all the subsets of S， P（S），2 S S = { a, b, c } 2 S = { , {a}, {b}, {c}, {a, b}, {a, c}, {b, c}, {a, b, c} } Observation: | 2S | = 2|S| ( 8 = 23 )