| Step | Hyp | Ref | Expression | 
						
							| 1 |  | suppss3.1 |  | 
						
							| 2 |  | suppss3.a |  | 
						
							| 3 |  | suppss3.z |  | 
						
							| 4 |  | suppss3.2 |  | 
						
							| 5 |  | suppss3.3 |  | 
						
							| 6 | 1 | oveq1i |  | 
						
							| 7 |  | simpl |  | 
						
							| 8 |  | eldifi |  | 
						
							| 9 | 8 | adantl |  | 
						
							| 10 |  | fnex |  | 
						
							| 11 | 4 2 10 | syl2anc |  | 
						
							| 12 |  | suppimacnv |  | 
						
							| 13 | 11 3 12 | syl2anc |  | 
						
							| 14 | 13 | eleq2d |  | 
						
							| 15 |  | elpreima |  | 
						
							| 16 | 4 15 | syl |  | 
						
							| 17 | 14 16 | bitrd |  | 
						
							| 18 | 17 | baibd |  | 
						
							| 19 | 18 | notbid |  | 
						
							| 20 | 19 | biimpd |  | 
						
							| 21 | 20 | expimpd |  | 
						
							| 22 |  | eldif |  | 
						
							| 23 |  | fvex |  | 
						
							| 24 |  | eldifsn |  | 
						
							| 25 | 23 24 | mpbiran |  | 
						
							| 26 | 25 | necon2bbii |  | 
						
							| 27 | 21 22 26 | 3imtr4g |  | 
						
							| 28 | 27 | imp |  | 
						
							| 29 | 7 9 28 5 | syl3anc |  | 
						
							| 30 | 29 2 | suppss2 |  | 
						
							| 31 | 6 30 | eqsstrid |  |