Virtual matrix family: a new concept for getting `extreme point´ solutions in the robust stability analysis of interval parameter matrices

Elaborates on a concept called the virtual matrix family which played a pivotal role in getting an extreme point solution for checking the robust stability of interval matrices. In this paper, main differences between the virtual matrix family and the actual matrix family are clearly explained and the unique and important features of this concept and its role in getting an extreme point solution are presented in detail, thereby making the proof of the main theorems as clear and elaborate as possible. It is then pointed out that this new concept can be used for getting an extreme point solution for checking the robust stability of even polytopes of matrices