*Wissenschaftliches Programm* *Liste der Vortragenden*

**Sektion 2**

Dienstag, 19.09.2000,
17.30–17.50 Uhr, POT 6

#### Harald Schmid, Universität Regensburg, NWF I - Mathematik

For piecewise continuous potentials which „behave like“ power functions at 0 and we investigate
whether the discrete eigenvalues of the radial Dirac operator accumulate at +1 or not. The main theorem is
an accumulation/nonaccumulation criterion where only the constants of the involved power functions
appear. We obtain this result by a method which is based on a Levinson type theorem for asymptotically
diagonal systems depending on some parameter, a comparison theorem for the principal solutions of
regular singular systems and some accumulation/nonaccumulation criteria for nonlinear singular
Sturm-Liouville problems. As a second application of this method, we get a similar criterion on the
eigenvalue accumulation at 0 for the radial Schrödinger equation.