q
Choose
b
i
³
0 and
a
j
³
0 so that
q
q
q
Let
q
q
q
q
Then ||
D
||
¥
=
1/
s
1
£
1
and
D
(j
w
0
)= (1/
s
1
) v
1
u
1
*
.
q