  We systematically examine the crustal torsional oscillations as varying the
stellar mass and radius, where we take into account the effect of electron
screening due to the inhomogeneity of electron distribution. In the
examinations, we adopt two different equations of state (EOSs) for the inner
crust region of neutron stars. As a result, we find that the frequencies depend
obviously on the EOS, even if the neutron star models are almost independent of
the EOS. That is, one could solve the degeneracy of the stellar models with
different EOS via the observations of shear oscillations frequencies.
Additionally, we find that the fundamental frequencies of the $l$-th order
torsional oscillations can reduce 6% due to the effect of electron screening,
which is independent of the adopted EOS and stellar models. This reduction of
frequencies can be crucial to make a constraints on the density dependence of
the nuclear symmetry energy, $L$, i.e., the constraint on $L$ can reduce ~15%
by the electron screening effect.
