  The Fourier decomposition was applied to the light curves of the short period
variable stars discovered by the OGLE team in Omega Cen. The phi_21 parameters
are confined in a narrow strip for periods between 0.042 d and 0.07 d. Toward
longer periods, there is an overlapping with the values obtained in the case of
galactic stars. Toward shorter periods, the tendency to decreasing phi_21
values is also verified. A careful analysis should take more details in
consideration: 1) Attention should be paid to the scatter in the distribution
of the phi_21 parameters around 0.050 d. By analogy to Cepheid light curves,
such a change can be the signature of a resonance between the fundamental mode
and a higher overtone. 2) The small bunch of points above the progression at
0.038 d suggests a different light curve family. Since this group of stars
shows a very small amplitude, it is possible that they are nonradial pulsators,
not necessarily radial pulsators in a higher overtone. 3) The very low phi_21
value emphasizes the anomalous light curve of OGLEGC 26. The fact that such a
light curve is observed in a Pop.II object is quite surprising, since V1719 Cyg
and V798 Cyg (whose light curves are similar) are very probably Pop.I stars. In
many cases, it seems that the phenomenon at the origin of the anomalous
brightness increase should be carefully evaluated when dealing with pulsating
star models.
