Comment on "Quantum electrodynamics near a photonic band gap: photon bound states and dressed atoms"

The applicability of the so-called isotropic and anisotropic complete photonic-band-gap (CPBG) models [S. John and J. Wang, Phys. Rev. Lett. {\bf 64}, 2418 (1990)] to capture essential features of the spontaneous emission (SE) of a fluorescent atom or molecule near a band-gap-edge of a CPBG structure is discussed. It is argued that, depending on the source position within a unit cell, the SE near the same CPBG edge can be either strongly enhanced or strongly depressed