Dolbeault J., Esteban M.J., Sere E.
On the eigenvalues of operators with gaps. Application to Dirac operators
(467K, Postscript)

ABSTRACT.  This paper is devoted to a general min-max characterization
of the eigenvalues in a gap of the essential spectrum
of a self-adjoint unbounded operator. We prove an abstract
theorem, then we apply it to the case of Dirac operators
with a Coulomb-like potential. The result is optimal for
the Coulomb potential.