| Step | Hyp | Ref | Expression | 
						
							| 1 |  | isirred2.1 |  | 
						
							| 2 |  | isirred2.2 |  | 
						
							| 3 |  | isirred2.3 |  | 
						
							| 4 |  | isirred2.4 |  | 
						
							| 5 |  | eldif |  | 
						
							| 6 |  | eldif |  | 
						
							| 7 |  | eldif |  | 
						
							| 8 | 6 7 | anbi12i |  | 
						
							| 9 |  | an4 |  | 
						
							| 10 | 8 9 | bitri |  | 
						
							| 11 | 10 | imbi1i |  | 
						
							| 12 |  | impexp |  | 
						
							| 13 |  | pm4.56 |  | 
						
							| 14 |  | df-ne |  | 
						
							| 15 | 13 14 | imbi12i |  | 
						
							| 16 |  | con34b |  | 
						
							| 17 | 15 16 | bitr4i |  | 
						
							| 18 | 17 | imbi2i |  | 
						
							| 19 | 12 18 | bitri |  | 
						
							| 20 | 11 19 | bitri |  | 
						
							| 21 | 20 | 2albii |  | 
						
							| 22 |  | r2al |  | 
						
							| 23 |  | r2al |  | 
						
							| 24 | 21 22 23 | 3bitr4i |  | 
						
							| 25 | 5 24 | anbi12i |  | 
						
							| 26 |  | eqid |  | 
						
							| 27 | 1 2 3 26 4 | isirred |  | 
						
							| 28 |  | df-3an |  | 
						
							| 29 | 25 27 28 | 3bitr4i |  |