| Step |
Hyp |
Ref |
Expression |
| 1 |
|
eqid |
|- ( Vtx ` G ) = ( Vtx ` G ) |
| 2 |
|
eqid |
|- ( iEdg ` G ) = ( iEdg ` G ) |
| 3 |
1 2
|
isuspgr |
|- ( G e. USPGraph -> ( G e. USPGraph <-> ( iEdg ` G ) : dom ( iEdg ` G ) -1-1-> { x e. ( ~P ( Vtx ` G ) \ { (/) } ) | ( # ` x ) <_ 2 } ) ) |
| 4 |
|
ssrab2 |
|- { x e. ( ~P ( Vtx ` G ) \ { (/) } ) | ( # ` x ) <_ 2 } C_ ( ~P ( Vtx ` G ) \ { (/) } ) |
| 5 |
|
f1ss |
|- ( ( ( iEdg ` G ) : dom ( iEdg ` G ) -1-1-> { x e. ( ~P ( Vtx ` G ) \ { (/) } ) | ( # ` x ) <_ 2 } /\ { x e. ( ~P ( Vtx ` G ) \ { (/) } ) | ( # ` x ) <_ 2 } C_ ( ~P ( Vtx ` G ) \ { (/) } ) ) -> ( iEdg ` G ) : dom ( iEdg ` G ) -1-1-> ( ~P ( Vtx ` G ) \ { (/) } ) ) |
| 6 |
4 5
|
mpan2 |
|- ( ( iEdg ` G ) : dom ( iEdg ` G ) -1-1-> { x e. ( ~P ( Vtx ` G ) \ { (/) } ) | ( # ` x ) <_ 2 } -> ( iEdg ` G ) : dom ( iEdg ` G ) -1-1-> ( ~P ( Vtx ` G ) \ { (/) } ) ) |
| 7 |
3 6
|
biimtrdi |
|- ( G e. USPGraph -> ( G e. USPGraph -> ( iEdg ` G ) : dom ( iEdg ` G ) -1-1-> ( ~P ( Vtx ` G ) \ { (/) } ) ) ) |
| 8 |
1 2
|
isushgr |
|- ( G e. USPGraph -> ( G e. USHGraph <-> ( iEdg ` G ) : dom ( iEdg ` G ) -1-1-> ( ~P ( Vtx ` G ) \ { (/) } ) ) ) |
| 9 |
7 8
|
sylibrd |
|- ( G e. USPGraph -> ( G e. USPGraph -> G e. USHGraph ) ) |
| 10 |
9
|
pm2.43i |
|- ( G e. USPGraph -> G e. USHGraph ) |