Articles
								
							
                        		Li Xin LIU, Yao Zhong SHI
                        	
							
							
							
								
                            	
                            
                        	
							
	                         	
	                         	
	                         	
	                         	
	                         	
	                         	
	                         	
	  							
	                         
							
								Based on the action of the mapping class group on the space of measured foliations, we construct a new boundary of the mapping class group and study the structure of this boundary. As an application, for any point in Teichmüller space, we consider the orbit of this point under the action of the mapping class group and describe the closure of this orbit in the Thurston compactification and the Gardiner-Masur compactification of Teichmüller space. We also construct some new points in the Gardiner-Masur boundary of Teichmüller space.