Analytic sets in the theory of commutative semigroups
Volume 228 / 2015
                    
                    
                        Studia Mathematica 228 (2015), 3-6                    
                                        
                        MSC: Primary 43A65; Secondary 03E15.                    
                                        
                        DOI: 10.4064/sm228-1-2                    
                                    
                                                Abstract
A problem about representations of countable, commutative semigroups leads to an analytic non-Borel set.
 
             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                         
                                                            