,9T]SEC;N "<( SETS"> ,EXAMPLES #A4 ,A 9T]SEC;N ;,B IS WRITT5 _% ,A.%,B _: #B4 ;,C 9T]SEC;N ;,D EQUALS ! EMPTY SET IS WRITT5 _% ,C.%,D .K _0 _: #C4 ,A 9T]SEC;N ;,B EQUALS ! SET ) ! ELE;TS TWO & F\R IS WRITT5 _% ,A.%,B .K .(2, 4.) _: #D4 ;,C 9T]SEC;N ;,D EQUALS ! SET ( ALL ;X S* T ;X IS AN ELE;T ( ;,C & ;X IS AN ELE;T ( ;,D IS WRITT5 _% ,C.%,D .K .(X "1 X @E ,C AND X @E ,D.) _: #A