We investigate the photon structure functions at small Bjorken variable x
in the framework of the holographic QCD, assuming dominance of the Pomeron
exchange. The quasi-real photon structure functions are expressed as
convolution of the Brower-Polchinski-Strassler-Tan (BPST) Pomeron kernel and
the known wave functions of the U(1) vector field in the five-dimensional AdS
space, in which the involved parameters in the BPST kernel have been fixed in
previous studies of the nucleon structure functions. The predicted photon
structure functions, as confronted with data, provide a clean test of the BPST
kernel. The agreement between theoretical predictions and data is demonstrated,
which supports applications of holographic QCD to hadronic processes in the
nonperturbative region. Our results are also consistent with those derived from
the parton distribution functions of the photon proposed by Gl\"uck, Reya, and
Schienbein, implying realization of the vector meson dominance in the present
model setup.Comment: 6 pages, 5 figures; v2: version accepted for publication in Phys.
Lett. B, Fig. 2 and clarifications added to Section