| Step | Hyp | Ref | Expression | 
						
							| 1 |  | orrvccel.1 |  | 
						
							| 2 |  | orrvccel.2 |  | 
						
							| 3 |  | orrvccel.4 |  | 
						
							| 4 |  | domprobsiga |  | 
						
							| 5 | 1 4 | syl |  | 
						
							| 6 |  | retop |  | 
						
							| 7 | 6 | a1i |  | 
						
							| 8 | 1 | rrvmbfm |  | 
						
							| 9 | 2 8 | mpbid |  | 
						
							| 10 |  | df-brsiga |  | 
						
							| 11 | 10 | oveq2i |  | 
						
							| 12 | 9 11 | eleqtrdi |  | 
						
							| 13 | 5 7 12 3 | orvcval4 |  | 
						
							| 14 |  | uniretop |  | 
						
							| 15 |  | rabeq |  | 
						
							| 16 | 14 15 | ax-mp |  | 
						
							| 17 | 16 | imaeq2i |  | 
						
							| 18 | 13 17 | eqtr4di |  |