| Step | Hyp | Ref | Expression | 
						
							| 1 |  | xporderlem.1 |  | 
						
							| 2 |  | df-br |  | 
						
							| 3 | 1 | eleq2i |  | 
						
							| 4 | 2 3 | bitri |  | 
						
							| 5 |  | opex |  | 
						
							| 6 |  | opex |  | 
						
							| 7 |  | eleq1 |  | 
						
							| 8 |  | opelxp |  | 
						
							| 9 | 7 8 | bitrdi |  | 
						
							| 10 | 9 | anbi1d |  | 
						
							| 11 |  | vex |  | 
						
							| 12 |  | vex |  | 
						
							| 13 | 11 12 | op1std |  | 
						
							| 14 | 13 | breq1d |  | 
						
							| 15 | 13 | eqeq1d |  | 
						
							| 16 | 11 12 | op2ndd |  | 
						
							| 17 | 16 | breq1d |  | 
						
							| 18 | 15 17 | anbi12d |  | 
						
							| 19 | 14 18 | orbi12d |  | 
						
							| 20 | 10 19 | anbi12d |  | 
						
							| 21 |  | eleq1 |  | 
						
							| 22 |  | opelxp |  | 
						
							| 23 | 21 22 | bitrdi |  | 
						
							| 24 | 23 | anbi2d |  | 
						
							| 25 |  | vex |  | 
						
							| 26 |  | vex |  | 
						
							| 27 | 25 26 | op1std |  | 
						
							| 28 | 27 | breq2d |  | 
						
							| 29 | 27 | eqeq2d |  | 
						
							| 30 | 25 26 | op2ndd |  | 
						
							| 31 | 30 | breq2d |  | 
						
							| 32 | 29 31 | anbi12d |  | 
						
							| 33 | 28 32 | orbi12d |  | 
						
							| 34 | 24 33 | anbi12d |  | 
						
							| 35 | 5 6 20 34 | opelopab |  | 
						
							| 36 |  | an4 |  | 
						
							| 37 | 36 | anbi1i |  | 
						
							| 38 | 4 35 37 | 3bitri |  |