Description: A set is an edge iff it is an indexed edge. (Contributed by AV, 17-Oct-2020) (Revised by AV, 8-Dec-2021)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | edgiedgb.i | |- I = ( iEdg ` G ) | |
| Assertion | edgiedgb | |- ( Fun I -> ( E e. ( Edg ` G ) <-> E. x e. dom I E = ( I ` x ) ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | edgiedgb.i | |- I = ( iEdg ` G ) | |
| 2 | edgval | |- ( Edg ` G ) = ran ( iEdg ` G ) | |
| 3 | 1 | eqcomi | |- ( iEdg ` G ) = I | 
| 4 | 3 | rneqi | |- ran ( iEdg ` G ) = ran I | 
| 5 | 2 4 | eqtri | |- ( Edg ` G ) = ran I | 
| 6 | 5 | eleq2i | |- ( E e. ( Edg ` G ) <-> E e. ran I ) | 
| 7 | elrnrexdmb | |- ( Fun I -> ( E e. ran I <-> E. x e. dom I E = ( I ` x ) ) ) | |
| 8 | 6 7 | bitrid | |- ( Fun I -> ( E e. ( Edg ` G ) <-> E. x e. dom I E = ( I ` x ) ) ) |