Date of Award

Spring 2019

Project Type


Program or Major


Degree Name

Doctor of Philosophy

First Advisor

Donald W Hadwin

Second Advisor

Junhao Shen

Third Advisor

Rita A Hibschweiler


The main part of the thesis relates to generalized Beurling-Helson-Lowdenslager theorems on the unit disk, in multiply connected domains, and in finite von Neumann algebras. I have also obtained results on approximate unitary equivalence of representations of separable ASH C*-algebras in a semifinite von Neumann algebra, extending results of D. Voiculescu. In the last part of the thesis, I give two characterizations of tracially nuclear C*-algebras.