J. Duoandikoetxea, J. Dolbeault, M. J. Esteban, L. Vega
Hardy-type estimates for Dirac operators.
(402K, Postscript)

ABSTRACT.  We prove some Hardy type inequalities related to the Dirac operator  
by elementary methods, for a large class of potentials, which even  
includes measure valued potentials. Optimality is achieved by the  
Coulomb potential. When potentials are smooth enough, our estimates  
provide some spectral information on the operator.