A categorical quotient in the category of dense constructible subsets
Tom 116 / 2009
                    
                    
                        Colloquium Mathematicum 116 (2009), 147-151                    
                                        
                        MSC: 14L30, 14L24.                    
                                        
                        DOI: 10.4064/cm116-2-1                    
                                    
                                                Streszczenie
A. A'Campo-Neuen and J. Hausen gave an example of an algebraic torus action on an open subset of the affine four space that admits no quotient in the category of algebraic varieties. We show that this example admits a quotient in the category of dense constructible subsets and thereby answer a question of A. Bia/lynicki-Birula.
 
             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                         
                                                            