Functional calculus for the Laguerre operator.

In this paper we study the boundedness of spectral multipliers associated to the multi-dimensional Laguerre operator L. It is well known that, for special values of the parameter alpha, the analysis of the Laguerre operator can be interpreted as the analysis of the Ornstein-Uhlenbeck operator acting on "polyradial" functions. Exploiting this relation, we prove that if M is a bounded holomorphic function in a sector S={z in C: | arg z |<arcsin |2/p-1|}, satisfying suitable Hormander type conditions on the boundary, then the spectral operator M(L) is bounded on L^p with respect to the Laguerre measure. We also prove that holomorphy in the sector S is a necessary condition for multipliers whose norm is invariant under dilations.