| Step | Hyp | Ref | Expression | 
						
							| 1 |  | eqid |  |-  ( Vtx ` G ) = ( Vtx ` G ) | 
						
							| 2 |  | eqid |  |-  ( iEdg ` G ) = ( iEdg ` G ) | 
						
							| 3 | 1 2 | ushgrf |  |-  ( G e. USHGraph -> ( iEdg ` G ) : dom ( iEdg ` G ) -1-1-> ( ~P ( Vtx ` G ) \ { (/) } ) ) | 
						
							| 4 |  | f1f |  |-  ( ( iEdg ` G ) : dom ( iEdg ` G ) -1-1-> ( ~P ( Vtx ` G ) \ { (/) } ) -> ( iEdg ` G ) : dom ( iEdg ` G ) --> ( ~P ( Vtx ` G ) \ { (/) } ) ) | 
						
							| 5 | 3 4 | syl |  |-  ( G e. USHGraph -> ( iEdg ` G ) : dom ( iEdg ` G ) --> ( ~P ( Vtx ` G ) \ { (/) } ) ) | 
						
							| 6 | 1 2 | isuhgr |  |-  ( G e. USHGraph -> ( G e. UHGraph <-> ( iEdg ` G ) : dom ( iEdg ` G ) --> ( ~P ( Vtx ` G ) \ { (/) } ) ) ) | 
						
							| 7 | 5 6 | mpbird |  |-  ( G e. USHGraph -> G e. UHGraph ) |