| Step | Hyp | Ref | Expression | 
						
							| 1 |  | dfdif2 |  | 
						
							| 2 |  | dfnul3 |  | 
						
							| 3 | 2 | uneq2i |  | 
						
							| 4 |  | un0 |  | 
						
							| 5 |  | unrab |  | 
						
							| 6 | 3 4 5 | 3eqtr3i |  | 
						
							| 7 |  | ianor |  | 
						
							| 8 |  | eluni |  | 
						
							| 9 | 8 | anbi1i |  | 
						
							| 10 |  | df-rex |  | 
						
							| 11 |  | elin |  | 
						
							| 12 | 11 | anbi2i |  | 
						
							| 13 |  | df-an |  | 
						
							| 14 | 12 13 | bitr3i |  | 
						
							| 15 | 14 | anbi2i |  | 
						
							| 16 |  | eldifsn |  | 
						
							| 17 |  | necom |  | 
						
							| 18 | 17 | anbi2i |  | 
						
							| 19 | 16 18 | bitri |  | 
						
							| 20 | 19 | anbi2i |  | 
						
							| 21 |  | ancom |  | 
						
							| 22 | 21 | anbi2ci |  | 
						
							| 23 |  | anass |  | 
						
							| 24 | 20 22 23 | 3bitri |  | 
						
							| 25 |  | an32 |  | 
						
							| 26 | 24 25 | bitr3i |  | 
						
							| 27 | 15 26 | bitr3i |  | 
						
							| 28 | 27 | exbii |  | 
						
							| 29 |  | 19.41v |  | 
						
							| 30 | 10 28 29 | 3bitri |  | 
						
							| 31 |  | rexnal |  | 
						
							| 32 | 9 30 31 | 3bitr2ri |  | 
						
							| 33 | 32 | con1bii |  | 
						
							| 34 | 7 33 | bitr3i |  | 
						
							| 35 | 34 | rabbii |  | 
						
							| 36 | 1 6 35 | 3eqtri |  | 
						
							| 37 | 36 | neeq1i |  | 
						
							| 38 |  | rabn0 |  | 
						
							| 39 | 37 38 | bitri |  |