Structured Robust Stability
Theorem
q
Define
q
D
:={
D
(·)
Î
RH
¥
:
D
(s
0
)
Î
D
for all s
0
Î
}
q
Theorem:
Let
b
>0
. The interconnected system is well-posed and
internally stable for all
D
(·)
Î
D
with ||
D
||
¥
<
1/
b
if and only if
q
