A FORMAL INTRODUCTION TO THE ц FRAMEWORK
The notion of mixed structured model perturbation and the s. s.v. ц are formally introduced in the first subsection. The skewed s. s. s. s is defined
in the second one. The s. s.v. p, can be considered as an extension of classical algebraic notions, namely the spectral radius and the spectral norm (third subsection). The fourth subsection introduces the Main Loop Theorem in the specific context of robust performance problems. The notion of p sensitivity is defined in the fifth subsection. The last subsection presents in a qualitative way some difficulties arising when using the fj, framework.