  In this paper, we revisit the connection between the Riemann-Roch theorem and
the zero energy solutions of the two-dimensional Dirac equation in the presence
of a delta-function like magnetic field. Our main result is the resolution of a
paradox - the fact that the Riemann-Roch theorem correctly predicts the number
of zero energy solutions of the Dirac equation despite counting what seems to
be the wrong type of functions.
