| Step | Hyp | Ref | Expression | 
						
							| 1 |  | isrrext.b |  | 
						
							| 2 |  | isrrext.v |  | 
						
							| 3 |  | isrrext.z |  | 
						
							| 4 |  | elin |  | 
						
							| 5 | 4 | anbi1i |  | 
						
							| 6 |  | fveq2 |  | 
						
							| 7 | 6 | eleq1d |  | 
						
							| 8 | 3 | eleq1i |  | 
						
							| 9 | 7 8 | bitr4di |  | 
						
							| 10 |  | fveqeq2 |  | 
						
							| 11 | 9 10 | anbi12d |  | 
						
							| 12 |  | eleq1 |  | 
						
							| 13 |  | fveq2 |  | 
						
							| 14 |  | fveq2 |  | 
						
							| 15 |  | fveq2 |  | 
						
							| 16 | 15 1 | eqtr4di |  | 
						
							| 17 | 16 | sqxpeqd |  | 
						
							| 18 | 14 17 | reseq12d |  | 
						
							| 19 | 18 2 | eqtr4di |  | 
						
							| 20 | 19 | fveq2d |  | 
						
							| 21 | 13 20 | eqeq12d |  | 
						
							| 22 | 12 21 | anbi12d |  | 
						
							| 23 | 11 22 | anbi12d |  | 
						
							| 24 |  | df-rrext |  | 
						
							| 25 | 23 24 | elrab2 |  | 
						
							| 26 |  | 3anass |  | 
						
							| 27 | 5 25 26 | 3bitr4i |  |