Arbitrary spin massless bosonic fields in d-dimensional anti-de Sitter space

Arbitrary spin free massless bosonic fields propagating in even $d$ - dimensional anti-de Sitter spacetime are investigated. Free wave equations of motion, subsidiary conditions and the corresponding gauge transformations for such fields are proposed. The lowest eigenvalues of the energy operator for the massless fields and the gauge parameter fields are derived. The results are formulated in $SO(d-1,2)$ covariant form as well as in terms of intrinsic coordinates. An inter-relation of two definitions of masslessness based on gauge invariance and conformal invariance is discussed