| Step | Hyp | Ref | Expression | 
						
							| 1 |  | 3oalem1.1 |  | 
						
							| 2 |  | 3oalem1.2 |  | 
						
							| 3 |  | 3oalem1.3 |  | 
						
							| 4 |  | 3oalem1.4 |  | 
						
							| 5 | 1 3 | chseli |  | 
						
							| 6 |  | r2ex |  | 
						
							| 7 | 5 6 | bitri |  | 
						
							| 8 | 2 4 | chseli |  | 
						
							| 9 |  | r2ex |  | 
						
							| 10 | 8 9 | bitri |  | 
						
							| 11 | 7 10 | anbi12i |  | 
						
							| 12 |  | elin |  | 
						
							| 13 |  | 4exdistrv |  | 
						
							| 14 | 11 12 13 | 3bitr4i |  | 
						
							| 15 | 1 2 3 4 | 3oalem2 |  | 
						
							| 16 | 15 | exlimivv |  | 
						
							| 17 | 16 | exlimivv |  | 
						
							| 18 | 14 17 | sylbi |  | 
						
							| 19 | 18 | ssriv |  |