Small
Gain Theorem

q**Small Gain Theorem:** Suppose *M*Î (*RH*¥)pxq . Then
the system is well-posed and internally stable for all *D** *Î*RH*¥ with

(a) ||*D*||¥ £1/g if and only if ||*M*||¥ < g ;

(b) ||*D*||¥ <1/g if and only if ||*M*||¥ £ g .