ϕ4-model and holography in four dimensions

The generating function of correlators of dual operators on the boundary of (A)dS4 space corresponding to the conformally coupled ϕ4-model is obtained up to first order in the coupling constant by using the conformal map between massless scalar fields in (Euclidean) Minkowski space and conformally coupled scalars on (Euclidean anti-) de Sitter space. Some exact classical solutions of the non-linear wave equation of massless (conformally coupled) ϕ3-, ϕ4- and ϕ6-models in D=6,4,3 Euclidean/Minkowski (AdS/dS) spaces are obtained.