| Step | 
						Hyp | 
						Ref | 
						Expression | 
					
						
							| 1 | 
							
								
							 | 
							3mix1 | 
							 |-  ( ph -> ( ph \/ ch \/ th ) )  | 
						
						
							| 2 | 
							
								1
							 | 
							imim1i | 
							 |-  ( ( ( ph \/ ch \/ th ) -> ps ) -> ( ph -> ps ) )  | 
						
						
							| 3 | 
							
								
							 | 
							3mix2 | 
							 |-  ( ch -> ( ph \/ ch \/ th ) )  | 
						
						
							| 4 | 
							
								3
							 | 
							imim1i | 
							 |-  ( ( ( ph \/ ch \/ th ) -> ps ) -> ( ch -> ps ) )  | 
						
						
							| 5 | 
							
								
							 | 
							3mix3 | 
							 |-  ( th -> ( ph \/ ch \/ th ) )  | 
						
						
							| 6 | 
							
								5
							 | 
							imim1i | 
							 |-  ( ( ( ph \/ ch \/ th ) -> ps ) -> ( th -> ps ) )  | 
						
						
							| 7 | 
							
								2 4 6
							 | 
							3jca | 
							 |-  ( ( ( ph \/ ch \/ th ) -> ps ) -> ( ( ph -> ps ) /\ ( ch -> ps ) /\ ( th -> ps ) ) )  | 
						
						
							| 8 | 
							
								
							 | 
							3jao | 
							 |-  ( ( ( ph -> ps ) /\ ( ch -> ps ) /\ ( th -> ps ) ) -> ( ( ph \/ ch \/ th ) -> ps ) )  | 
						
						
							| 9 | 
							
								7 8
							 | 
							impbii | 
							 |-  ( ( ( ph \/ ch \/ th ) -> ps ) <-> ( ( ph -> ps ) /\ ( ch -> ps ) /\ ( th -> ps ) ) )  |