Extension
to Nonlinear Time Varying Uncertainty

qSuppose *D** *Î *D**N*** ** is a structured Nonlinear (Time-varying) Uncertainty and suppose *D* is constant scaling matrix
such that *D**D**D**-1* Î *D**N*** **. (Note that we do not require *D**D**=**D**D*.)

Then a sufficient stability condition for all *D* Î *D**N* with ||*D*||¥< *1*, is (by small gain theorem)

||*D**-1**G(s)D*||¥ £ *1*