Root-Clustering Criteria (I): The Composite-Matrix Approach
SHAUL GUTMAN, Fabien Chojnowski · IMA Journal of Mathematical Control and Information · 1989
In a series of articles we investigate different approaches to root clustering criteria. In particular, given A ε C n × n and an algebraic region A ⊂ C, we are looking for a criterion (a single set of inequalities) ensuring the inclusion Σ( A ) ⊂ A . Here, in the first article, we collect previous ideas on transformable regions and composite matrices, state new results, and correct and refine others.