This thesis discusses some structural problems in linear
multivariable systems theory and is based on certain published
papers of the candidate. The material divides into two parts, the first of which deals with composite systems
and considers the type of structural problems that occur when
systems are interconnected to form other (composite) systems.
The framework developed in this discussion then leads naturally
to a consideration of the theory of invariants of multivariable
systems, which forms the second part. [Continues.]
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy at Loughborough University.