| Step | Hyp | Ref | Expression | 
						
							| 1 |  | breq1 |  | 
						
							| 2 |  | atcv0eq |  | 
						
							| 3 | 1 2 | sylan9bbr |  | 
						
							| 4 | 3 | biimpd |  | 
						
							| 5 | 4 | ex |  | 
						
							| 6 | 5 | com23 |  | 
						
							| 7 | 6 | 3adant1 |  | 
						
							| 8 | 7 | imp |  | 
						
							| 9 |  | oveq1 |  | 
						
							| 10 |  | atelch |  | 
						
							| 11 |  | chjidm |  | 
						
							| 12 | 10 11 | syl |  | 
						
							| 13 | 9 12 | sylan9eq |  | 
						
							| 14 | 13 | eqcomd |  | 
						
							| 15 | 14 | eleq1d |  | 
						
							| 16 | 15 | ex |  | 
						
							| 17 | 16 | ibd |  | 
						
							| 18 | 17 | impcom |  | 
						
							| 19 |  | atcveq0 |  | 
						
							| 20 | 18 19 | sylan2 |  | 
						
							| 21 | 20 | biimpd |  | 
						
							| 22 | 21 | exp32 |  | 
						
							| 23 | 22 | com34 |  | 
						
							| 24 | 23 | imp |  | 
						
							| 25 | 24 | 3adant2 |  | 
						
							| 26 | 25 | imp |  | 
						
							| 27 | 8 26 | impbid |  |