Roth, Thomas2015-05-062015-05-062015-05-06http://hdl.handle.net/10539/17629A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, February 15, 2015.In this thesis, the forward and inverse Spectral Theory for first order Hermitian systems with complex potentials and periodic boundary conditions are studied. The aim of this work is to prove two inverse periodicity Theorems and two uniqueness results for determinants of quasiperiodic boundary value problems.enBoundary value problems.Spectral theory (Mathematics)Differential operators.Thesis