Ben-Gurion University, Beer-Sheva, Israel
We consider the Sturm-Liouville operator with a potential q(x) on a finite interval with the Dirichlet, Neumann, periodic, or anti-periodic boundary conditions. It is well known that for real-valued potentials the eigenvalues of the Dirichlet and Neumann problems are simple, while the ones of the periodic and anti-periodic problems are at most of multiplicity 2. The same properties hold only asymptotically for complex-valued potentials. We show that otherwise there is no restrictions on the multiplicities: each of the above spectra may contain finitely many multiple points of an arbitrary multiplicity.
Please join us for refreshments before the lecture at 2:30p.m. in room 353 Jabara Hall.
[ Fall 1999]