上海大孝 SHIANCH AI JLAO IONG LNTVERSTY 9.1 Preliminaries A: A set in Z2 with elements of a=(a,, a2) 廷A ●AcB C=A∪B D=A∪B A∩B= A=wwE A A-B={w∈A,wgB=A∩B9.1 Preliminaries • A: A set in Z2 with elements of a = (a1 , a2 )