| Step | Hyp | Ref | Expression | 
						
							| 1 |  | dff13 |  | 
						
							| 2 |  | fveq2 |  | 
						
							| 3 |  | df-ov |  | 
						
							| 4 | 2 3 | eqtr4di |  | 
						
							| 5 | 4 | eqeq1d |  | 
						
							| 6 |  | eqeq1 |  | 
						
							| 7 | 5 6 | imbi12d |  | 
						
							| 8 | 7 | ralbidv |  | 
						
							| 9 | 8 | ralxp |  | 
						
							| 10 |  | fveq2 |  | 
						
							| 11 |  | df-ov |  | 
						
							| 12 | 10 11 | eqtr4di |  | 
						
							| 13 | 12 | eqeq2d |  | 
						
							| 14 |  | eqeq2 |  | 
						
							| 15 |  | vex |  | 
						
							| 16 |  | vex |  | 
						
							| 17 | 15 16 | opth |  | 
						
							| 18 | 14 17 | bitrdi |  | 
						
							| 19 | 13 18 | imbi12d |  | 
						
							| 20 | 19 | ralxp |  | 
						
							| 21 | 20 | 2ralbii |  | 
						
							| 22 | 9 21 | bitri |  | 
						
							| 23 | 22 | anbi2i |  | 
						
							| 24 | 1 23 | bitri |  |