Chapter 3 6 5.The distance of x&y awg-小-区g-j月 I[x2,,i,]'&y=1J1,…,]',ieV,】eV SJTu cor Obviously,d(x,y)=0,if and only if =y 5. The distance of x & y 2 1 1 2 ( ) ( )                n i i i d x , y x y x - y , x - y x y x  [ 1 , 2 , , ] & y  [ 1 , 2 , , ] , x  V , y  V T n T n x x  x y y  y Obviously, d ( x , y )  0 , i f a n d o n ly i f x  y y d ( x , y ) Chapter 3 6