  The electromagnetic characteristics of the fractional quantum Hall states are
studied by formulating an effective vector-field theory that takes into account
projection to the exact Landau levels from the beginning. The effective theory
is constructed, via bosonization, from the electromagnetic response of an
incompressible and uniform state. It does not refer to either the
composite-boson or composite-fermion picture, but properly reproduces the
results of the standard bosonic and fermionic Chern-Simons approaches, thus
revealing the universality of the long-wavelength characteristics of the
quantum Hall states and the associated quasiparticles. In particular, the
dual-field Lagrangian of Lee and Zhang is obtained without invoking the
composite-boson picture. An argument is also given to verify, within a
vector-field version of the fermionic Chern-Simons theory, the identification
by Goldhaber and Jain of a composite fermion as a dressed electron.
