TITLE: 
                        
                            Revealed Cores: Characterizations and Structure
                                
                                
                                    AUTHORS: 
                                            Stefano Vannucci 
                                                    
                                                        KEYWORDS: 
                        Core, Choice Functions, Dominance Digraphs, Revealed Preference 
                                                    
                                                    
                                                        JOURNAL NAME: 
                        Applied Mathematics,  
                        Vol.6 No.14, 
                        December
                                                        30,
                        2015
                                                    
                                                    
                                                        ABSTRACT: Characterizations of the classes of all choice functions that select the cores or the externally stable cores induced by an underlying revealed dominance digraph are provided. Relying on such characterizations, the basic order-theoretic structure of the corresponding sets of revealed cores is also analyzed. In particular, it is shown that the poset of all revealed cores ordered by set inclusion is a median meet semilattice: therefore, any profile of revealed cores may be aggregated by means of the simple majority rule.