H¥ Norm as Induced
H2 Norm

§Let *G*(*s*) be a *p× q* transfer matrix. Then a **multiplication operator** is defined as *M**G**: **L**2 *® *L**2
**, M**G** f=Gf
*

Then

To show
that ||*G*||¥ is the least upper bound, first choose a
frequency *w*0 where is maximum, i.e.,