| Step | Hyp | Ref | Expression | 
						
							| 1 |  | df-rab |  | 
						
							| 2 |  | simp2 |  | 
						
							| 3 |  | zcn |  | 
						
							| 4 | 3 | 3ad2ant1 |  | 
						
							| 5 | 2 4 | npcand |  | 
						
							| 6 |  | eluzadd |  | 
						
							| 7 | 6 | ancoms |  | 
						
							| 8 | 7 | 3adant2 |  | 
						
							| 9 | 5 8 | eqeltrrd |  | 
						
							| 10 | 9 | 3expib |  | 
						
							| 11 | 10 | adantr |  | 
						
							| 12 |  | eluzelcn |  | 
						
							| 13 | 12 | a1i |  | 
						
							| 14 |  | eluzsub |  | 
						
							| 15 | 14 | 3expia |  | 
						
							| 16 | 15 | ancoms |  | 
						
							| 17 | 13 16 | jcad |  | 
						
							| 18 | 11 17 | impbid |  | 
						
							| 19 | 18 | eqabcdv |  | 
						
							| 20 | 1 19 | eqtrid |  |