Perfect sets of finite class without the extension property
Volume 126 / 1997
                    
                    
                        Studia Mathematica 126 (1997), 161-170                    
                                        
                        DOI: 10.4064/sm-126-2-161-170                    
                                    
                                                Abstract
We prove that generalized Cantor sets of class α, α ≠ 2 have the extension property iff α < 2. Thus belonging of a compact set K to some finite class α cannot be a characterization for the existence of an extension operator. The result has some interconnection with potential theory.
 
             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                         
                                                            