  The amplification of disk oscillations resulting from nonlinear resonant
couplings between the oscillations and a disk deformation is examined. The disk
is geometrically thin and general relativistic with a non-rotating central
source. A Lagrangian formulation is adopted. The author examined the same
problem a few years ago, but here we derive a general stability criterion in a
more perspective way. Another distinct point from the previous work is that in
addition to the case where the deformation is a warp, the case where the
deformation is a one-armed pattern symmetric with respect to the equatorial
plane is considered. The results obtained show that in addition to the previous
results that the inertial-acoustic mode and g-mode oscillations are amplified
by horizontal resonance in warped disks, they also amplified by horizontal
resonance in disks deformed by one-armed pattern symmetric with respect to the
equatorial plane. If we consider local oscillations that are localized around
boundaries of their propagation region, the resonance occurs at $4r_{\rm g}$,
where $r_{\rm g}$ is the Schwarzschild radius. If nonlocal oscillations are
considered, frequency ranges of oscillations where oscillations are resonantly
amplified are specified.
