| Step | Hyp | Ref | Expression | 
						
							| 1 |  | islinds.b |  | 
						
							| 2 |  | elex |  | 
						
							| 3 |  | fveq2 |  | 
						
							| 4 | 3 | pweqd |  | 
						
							| 5 |  | breq2 |  | 
						
							| 6 | 4 5 | rabeqbidv |  | 
						
							| 7 |  | df-linds |  | 
						
							| 8 |  | fvex |  | 
						
							| 9 | 8 | pwex |  | 
						
							| 10 | 9 | rabex |  | 
						
							| 11 | 6 7 10 | fvmpt |  | 
						
							| 12 | 2 11 | syl |  | 
						
							| 13 | 12 | eleq2d |  | 
						
							| 14 |  | reseq2 |  | 
						
							| 15 | 14 | breq1d |  | 
						
							| 16 | 15 | elrab |  | 
						
							| 17 | 13 16 | bitrdi |  | 
						
							| 18 | 8 | elpw2 |  | 
						
							| 19 | 1 | sseq2i |  | 
						
							| 20 | 18 19 | bitr4i |  | 
						
							| 21 | 20 | anbi1i |  | 
						
							| 22 | 17 21 | bitrdi |  |