  We present a microscopic picture of quantum transport in the Aharonov-Bohm
(AB) interferometer taking into account electron interaction within the Hartree
and the spin density functional theory approximations. We discuss the structure
of the edge states for different number of the Landau levels in the leads,
their coupling to the states in the central island and the formation of
compressible/incompressible strips in the interferometer. Based on our results
we discuss the existing theories of the unexpected AB periodicity, which
essentially rely on specific phenomenological models of the states and their
coupling in the interferometer. Our work provides a basis for such the
theories, giving a detailed microscopic description of the propagating states
and the global electrostatics in the system at hand.
