| Step | Hyp | Ref | Expression | 
						
							| 1 |  | isubgriedg.v |  | 
						
							| 2 |  | isubgriedg.e |  | 
						
							| 3 |  | ssidd |  | 
						
							| 4 | 1 2 | isisubgr |  | 
						
							| 5 | 3 4 | mpdan |  | 
						
							| 6 | 2 | uhgrfun |  | 
						
							| 7 |  | funrel |  | 
						
							| 8 | 6 7 | syl |  | 
						
							| 9 | 1 2 | uhgrf |  | 
						
							| 10 |  | ffvelcdm |  | 
						
							| 11 |  | eldifi |  | 
						
							| 12 | 11 | elpwid |  | 
						
							| 13 | 10 12 | syl |  | 
						
							| 14 | 13 | rabeqcda |  | 
						
							| 15 | 14 | eqimsscd |  | 
						
							| 16 | 9 15 | syl |  | 
						
							| 17 |  | relssres |  | 
						
							| 18 | 8 16 17 | syl2anc |  | 
						
							| 19 | 18 | opeq2d |  | 
						
							| 20 | 5 19 | eqtrd |  |