Smooth operators for the regular representation on homogeneous spaces
Volume 142 / 2000
                    
                    
                        Studia Mathematica 142 (2000), 149-157                    
                                        
                        DOI: 10.4064/sm-142-2-149-157                    
                                    
                                                Abstract
A necessary and sufficient condition for a bounded operator on $L^2(M)$, M a Riemannian compact homogeneous space, to be smooth under conjugation by the regular representation is given. It is shown that, if all formal 'Fourier multipliers with variable coefficients' are bounded, then they are also smooth. In particular, they are smooth if M is a rank-one symmetric space.
 
             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                         
                                                            