| Step | Hyp | Ref | Expression | 
						
							| 1 |  | cnnrg |  | 
						
							| 2 |  | resubdrg |  | 
						
							| 3 | 2 | simpli |  | 
						
							| 4 |  | df-refld |  | 
						
							| 5 | 4 | subrgnrg |  | 
						
							| 6 | 1 3 5 | mp2an |  | 
						
							| 7 | 2 | simpri |  | 
						
							| 8 | 6 7 | pm3.2i |  | 
						
							| 9 |  | rezh |  | 
						
							| 10 |  | reofld |  | 
						
							| 11 |  | ofldchr |  | 
						
							| 12 | 10 11 | ax-mp |  | 
						
							| 13 | 9 12 | pm3.2i |  | 
						
							| 14 |  | recusp |  | 
						
							| 15 |  | reust |  | 
						
							| 16 | 14 15 | pm3.2i |  | 
						
							| 17 |  | rebase |  | 
						
							| 18 |  | eqid |  | 
						
							| 19 |  | eqid |  | 
						
							| 20 | 17 18 19 | isrrext |  | 
						
							| 21 | 8 13 16 20 | mpbir3an |  |