  We study the self-adjoint Pauli operators that can be realized as the square
of a self-adjoint Dirac operator and correspond to a magnetic field consisting
of a finite number of Aharonov-Bohm solenoids and a regular part, and prove an
Aharonov-Casher type formula for the number of zero-modes for these operators.
We also see that essentially only one of the Pauli operators are spin-flip
invariant, and this operator does not have any zero-modes.
