Structured Perturbation
q
Problem: Given
M
Î
C
p
´
q
, find a smallest
D
Î
D
q
D
=
{diag[
d
1
I
r1
, …,
d
s
I
rs
,
D
1
, …,
D
F
]
Î
C
p
´
q
:
d
i
Î
C
,
D
j
Î
C
m
j
´
m
j
}
q
such that
det(
I-M
D
)
=0.
q
q
q
q
q
We shall call 1/
a
min
as structured singular value (SSV).
q