This book contains two fundamental papers. The first is, in essence, a short monograph devoted to the theory of periodic motions in singularly perturbed systems

Intensive research in matrix completions, moments, and sums of Hermitian squares has yielded a multitude of results in recent decades. This book provides a comp

This volume, dedicated to Carl Pearcy on the occasion of his 60th birthday, presents recent results in operator theory, nonselfadjoint operator algebras, measur