J. Dolbeault, M.J. Esteban, E. Sere
Variational characterization for eigenvalues of Dirac operators
(1036K, Postscript)

ABSTRACT.  In this paper we give two different variational characterizations 
for the eigenvalues of of $H+V$ where $H$ denotes the free 
Dirac operator and $V$ is a scalar potential. 
The first one is a min-max involving a Rayleigh
quotient. The second one consists in minimizing an 
appropriate nonlinear functional. Both methods can be 
applied to potentials which have
singularities as strong as the Coulomb potential.