P-ideal dichotomy and Tukey order
Tom 267 / 2024
                    
                    
                        Fundamenta Mathematicae 267 (2024), 181-194                    
                                        
                        MSC: Primary 03E02; Secondary 03E10, 05D10                    
                                        
                        DOI: 10.4064/fm240323-26-6                    
                                            
                            Opublikowany online: 30 August 2024                        
                                    
                                                Streszczenie
The P-ideal dichotomy is a simple and natural principle about P-ideals of countable subsets of some index set. It has proven to be particularly useful in problems involving sequential convergence in topological spaces. This is explored further here with the aim to relate it to the theory of Tukey reductions of directed sets.