The Carathéodory–Fejér interpolation on the polydisc
Tom 254 / 2020
                    
                    
                        Studia Mathematica 254 (2020), 265-293                    
                                        
                        MSC: Primary 47A20, 47A56, 47B35; Secondary 30E05, 30H05, 30H10.                    
                                        
                        DOI: 10.4064/sm190314-18-8                    
                                            
                            Opublikowany online: 6 April 2020                        
                                    
                                                Streszczenie
We give an algorithm for finding a solution to the Carathéodory–Fejér interpolation problem on the polydisc, whenever a solution exists. A necessary condition for the existence of a solution becomes apparent from this algorithm. A generalization of the well-known theorem due to Nehari has been obtained. A proof of the Korányi–Pukánszky theorem also follows from these ideas.
 
             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                         
                                                            