promptly. I would also like to thank all the members ofsta

• exposé
• cours - matière : mathematics

Acknowledgements I would like to thank my supervisor, Prof. Nicholas Young, for the patient guidance, encouragement and advice he has provided throughout my time as his student. I have been extremely lucky to have a supervisor who cared so much about my work, and who responded to my questions and queries so promptly. I would also like to thank all the members of staff at Newcastle and Lancaster Universities who helped me in my supervisor's absence.

• space of complex k×k matrices
• necessary conditions for the existence of a solution
• nevanlinna
• pick problem arises as a consequence of robust control theory
• pick problem
• complete study of the kind of control problems
• control theory
• solution
• systems